The document discusses hybrid rocket motors. Hybrid rockets use a solid fuel and liquid or gaseous oxidizer. They offer inherent safety advantages over solid and liquid rockets but traditionally have had low fuel regression rates, requiring complex multi-port designs for launch systems. Recent work has focused on ways to increase regression rates through techniques like adding oxidizing agents or metal particles to the fuel grain. Solid cryogenic hybrids, using frozen fuels at cryogenic temperatures, have shown potential for 3-5 times faster regression rates than traditional polymers. Overall, hybrid systems provide potential benefits but challenges in fuel design have limited their application for orbital launch.
6th International Disaster and Risk Conference IDRC 2016 Integrative Risk Management - Towards Resilient Cities. 28 August - 01 September 2016 in Davos, Switzerland
This document summarizes an experimental investigation into the regression rate behavior of hydroxyl-terminated polybutadiene (HTPB) solid fuel burning with oxygen in a hybrid rocket motor. Key findings include:
1) Real-time x-ray radiography was used to obtain instantaneous solid fuel regression rate data at many axial locations in the motor. Regression rates had a strong dependence on axial location near the head-end of the motor.
2) Thermocouple measurements indicated fuel surface temperatures between 930 and 1190 K. The estimated activation energy of 11.5 kcal/mole suggests the overall regression process is governed by physical desorption of high-molecular weight fragments from the fuel surface.
This document provides a survey and analysis of fuel cell technology. It begins with an introduction to fuel cells and their benefits over traditional power sources. It then presents a mathematical model of a hydrogen fuel cell, including an equivalent circuit diagram and polarization curve. The model is expanded to account for varying parameters such as temperature, pressures, and gas flow rates. The model equations calculate values like open circuit voltage and exchange current based on these parameters. Finally, the document demonstrates how to extract specific fuel cell stack parameters, such as number of cells and nominal air flow rate, from a manufacturer's datasheet.
Investigating a conventional and retrofit power plant on-board a Roll-on-Roll...Janie Ling Chin
This document summarizes a study that used life cycle assessment (LCA) to investigate the environmental impacts of a conventional power plant and a retrofitted power plant on a roll-on/roll-off cargo ship. The study found that the conventional power plant significantly impacted the environment through materials consumption, fuel combustion emissions over 30 years of operation, and waste disposal. Retrofitting the power plant with emerging technologies like photovoltaics, batteries, and electrical connections could potentially reduce several environmental impacts by 4-7 orders of magnitude according to scenario analysis, though impacts may shift between categories. The retrofitted system needs careful design and management to achieve environmental benefits while avoiding other detrimental impacts.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses the evolution and capabilities of the AASHTO Pavement ME Design (PMED) software for modeling asphalt pavement cracking. It describes the inputs, response models, and cracking models used in PMED. The key cracking models are for bottom-up fatigue cracking, top-down cracking, transverse cracking, and reflection cracking. The document outlines the limitations of early empirical models and how PMED has developed more mechanistic models based on stress/strain responses and fracture mechanics. It provides details on the calibration factors used to adjust PMED predictions based on local conditions and data.
Computational Fluid Dynamics (CFD) Analysis of Natural Convection of Converge...IJERA Editor
Computational Fluid Dynamics (CFD) analysis was carried out for the convergent-divergent fins arranged inline and staggered on the base plate as per the experimental setup provided in the technical paper [1]. This paper reports on the validation of results of modeling and simulation in CFD. The simulation was carried out using the ANSYS 12.0 as the CFD modeling software. The main objective of the CFD analysis was to calculate the temperature distribution on the surface of the base plate and surface of the convergent-divergent fins for the given inline and staggered arrangement of fins due to the effect of natural convection heat transfer for different heat power inputs, and also to compare the CFD results with the experimental results.
A comparative life cycle assessment of marine power systems_FinalJanie Ling Chin
This document summarizes a study that performed a comparative life cycle assessment of different marine power systems for cargo ships. The study compared a conventional diesel mechanical system to an advanced retrofit system and new-build system incorporating emerging technologies. The life cycle assessment models developed for each system's components showed that the retrofit and new-build systems consumed less fuel and emitted fewer emissions during operation, but required more resources during manufacture. For most environmental impact categories, both advanced systems achieved reductions compared to the conventional system, with the new-build system showing the greatest potential reductions. However, some impact categories like ecotoxicity and fossil fuel depletion increased more for the advanced systems. The study provides insights on the relative environmental performances of different marine power system
6th International Disaster and Risk Conference IDRC 2016 Integrative Risk Management - Towards Resilient Cities. 28 August - 01 September 2016 in Davos, Switzerland
This document summarizes an experimental investigation into the regression rate behavior of hydroxyl-terminated polybutadiene (HTPB) solid fuel burning with oxygen in a hybrid rocket motor. Key findings include:
1) Real-time x-ray radiography was used to obtain instantaneous solid fuel regression rate data at many axial locations in the motor. Regression rates had a strong dependence on axial location near the head-end of the motor.
2) Thermocouple measurements indicated fuel surface temperatures between 930 and 1190 K. The estimated activation energy of 11.5 kcal/mole suggests the overall regression process is governed by physical desorption of high-molecular weight fragments from the fuel surface.
This document provides a survey and analysis of fuel cell technology. It begins with an introduction to fuel cells and their benefits over traditional power sources. It then presents a mathematical model of a hydrogen fuel cell, including an equivalent circuit diagram and polarization curve. The model is expanded to account for varying parameters such as temperature, pressures, and gas flow rates. The model equations calculate values like open circuit voltage and exchange current based on these parameters. Finally, the document demonstrates how to extract specific fuel cell stack parameters, such as number of cells and nominal air flow rate, from a manufacturer's datasheet.
Investigating a conventional and retrofit power plant on-board a Roll-on-Roll...Janie Ling Chin
This document summarizes a study that used life cycle assessment (LCA) to investigate the environmental impacts of a conventional power plant and a retrofitted power plant on a roll-on/roll-off cargo ship. The study found that the conventional power plant significantly impacted the environment through materials consumption, fuel combustion emissions over 30 years of operation, and waste disposal. Retrofitting the power plant with emerging technologies like photovoltaics, batteries, and electrical connections could potentially reduce several environmental impacts by 4-7 orders of magnitude according to scenario analysis, though impacts may shift between categories. The retrofitted system needs careful design and management to achieve environmental benefits while avoiding other detrimental impacts.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses the evolution and capabilities of the AASHTO Pavement ME Design (PMED) software for modeling asphalt pavement cracking. It describes the inputs, response models, and cracking models used in PMED. The key cracking models are for bottom-up fatigue cracking, top-down cracking, transverse cracking, and reflection cracking. The document outlines the limitations of early empirical models and how PMED has developed more mechanistic models based on stress/strain responses and fracture mechanics. It provides details on the calibration factors used to adjust PMED predictions based on local conditions and data.
Computational Fluid Dynamics (CFD) Analysis of Natural Convection of Converge...IJERA Editor
Computational Fluid Dynamics (CFD) analysis was carried out for the convergent-divergent fins arranged inline and staggered on the base plate as per the experimental setup provided in the technical paper [1]. This paper reports on the validation of results of modeling and simulation in CFD. The simulation was carried out using the ANSYS 12.0 as the CFD modeling software. The main objective of the CFD analysis was to calculate the temperature distribution on the surface of the base plate and surface of the convergent-divergent fins for the given inline and staggered arrangement of fins due to the effect of natural convection heat transfer for different heat power inputs, and also to compare the CFD results with the experimental results.
A comparative life cycle assessment of marine power systems_FinalJanie Ling Chin
This document summarizes a study that performed a comparative life cycle assessment of different marine power systems for cargo ships. The study compared a conventional diesel mechanical system to an advanced retrofit system and new-build system incorporating emerging technologies. The life cycle assessment models developed for each system's components showed that the retrofit and new-build systems consumed less fuel and emitted fewer emissions during operation, but required more resources during manufacture. For most environmental impact categories, both advanced systems achieved reductions compared to the conventional system, with the new-build system showing the greatest potential reductions. However, some impact categories like ecotoxicity and fossil fuel depletion increased more for the advanced systems. The study provides insights on the relative environmental performances of different marine power system
Combustion and Mixing Analysis of a Scramjet Combustor Using CFDijsrd.com
This document summarizes a computational fluid dynamics (CFD) study of combustion and mixing in a scramjet combustor. The study uses ANSYS Fluent software to model flow inside a scramjet combustor geometry for hydrogen, diesel, and methane fuels. The objectives are to determine the flow field and maximize thrust at a Mach number of 2. Key findings include that combustion increases recirculation behind the flameholder strut compared to mixing alone, and shockwaves from the strut facilitate combustion ignition in regions with fuel-air mixing. Meshing of the combustor geometry and strut are discussed.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The document discusses rocket engine design and performance. It covers ideal rocket equations and assumptions, the basic components of a rocket including the combustion chamber and de Laval nozzle. Key performance parameters like characteristic velocity, thrust coefficient, and effective exhaust velocity are defined. The relationships between chamber pressure, temperature, nozzle expansion ratio and these velocities are explained. Mixture ratio and its effect on specific impulse is also discussed for liquid oxygen and liquid hydrogen propellants.
ENHANCEMENT OF THERMAL EFFICIENCY OF NANOFLUID FLOWS IN A FLAT SOLAR COLLECTO...Barhm Mohamad
Flat plate solar collector (FPSC) is popular for their low cost, simplicity, and ease of installation and operation. In this work, FPSC thermal performance was analyzed. It's compared to diamond/H2O nanofluids. The volume percentage and kind of nanoparticles are analyzed numerically that validation with experimental data available in the literature. The hot climate of Iraq is employed to approximate the model. The numerical study is performed by using ANSYS/FLUENT software to simulate the case study of problem. Due to less solar intensity after midday, temperatures reduction. The greatest collector thermal efficiency is 68.90% with 1% ND/water nanofluid, a 12.2% increase over pure water. The efficiency of 1% nanofluid is better than other concentrations because of a change in physical properties and an increase in thermal conductivity. Since the intensity of radiation affects the outlet temperature from the solar collector and there is a direct link between them, this increases the efficiency of the solar collector, especially around 12:30 pm at the optimum efficiency.
Investigating the implications of a new-build hybrid power system for RoRo ca...Janie Ling Chin
This document summarizes a study that used life cycle assessment to evaluate the environmental impacts of a proposed hybrid power system for roll-on/roll-off cargo ships from manufacturing to end of life, compared to a conventional power system. The study estimated resource usage, emissions, and impacts and identified operating diesel generators and disposing of metallic scrap as particularly significant processes. It verified the environmental benefits of the hybrid system in most impact categories.
The UCLA Rocket Project has continued developing its custom hybrid rocket engine called HyPE for the 6th Intercollegiate Rocket Engineering Competition. The HyPE uses paraffin wax and aluminum powder fuel with nitrous oxide oxidizer, and is capable of propelling a 10 pound payload to 25,000 feet. Students designed and built a carbon fiber airframe, recovery system, avionics, and ground support equipment. Aerodynamic analysis was performed to optimize the rocket's drag, and a 4.5:1 LD Haack nose cone was selected to reduce wave drag at supersonic speeds. The project involves over 30 students and aims to compete in and win the advanced category of IREC.
This document describes a numerical simulation of magnetohydrodynamic instabilities in nuclear fusion plasma. The simulation analyzed plasma characteristics like magnetic compression and tension. It found that strong initial internal and external magnetic fields can correct for natural MHD instabilities, increasing magnetic confinement time. The best configuration applied a poloidal field of similar magnitude to the toroidal field and a constant external vertical field, increasing confinement time by 400%.
This document discusses atmospheric chemistry models and their use in quantifying atmospheric concentrations and fluxes. Global 3D models divide the atmosphere into grid boxes and use the continuity equation to track species concentrations over time, accounting for transport, chemistry, emissions and deposition. Transport is parameterized using turbulence and convection schemes. Chemistry is solved using operator splitting and implicit methods. Models are evaluated and improved using atmospheric observations from satellites, aircraft and surface sites through data assimilation techniques like inverse modeling. Examples are given of various applications of the GEOS-CHEM global model.
This document discusses the design and analysis of an airborne radome. It begins with an abstract that outlines the purpose of radomes to protect microwave subsystems from environmental effects while maintaining electromagnetic transparency. It then provides a table of contents and overview of the various chapters that will analyze radome design using Creo and ANSYS software, composite materials testing and analysis, and structural analysis including dynamic analysis and pressure testing. The document focuses on the design, analysis, and testing of a composite material radome.
Optimal routing development based on real voyage data presented by_sewonkimSEWON KIM
This document summarizes a joint session between Korean and Japanese organizations on developing optimal routing for smart ships based on real voyage data. It discusses challenges in autonomous vessel technology including route optimization. A case study was presented on estimating fuel consumption for a container ship voyage from Yokohama to San Francisco using modeled resistance calculations calibrated to real voyage data. The optimal route reduced fuel consumption by 4% compared to the great circle route. The session concluded autonomous vessels are becoming reality sooner than expected due to increasing collaboration between industries and researchers.
IRJET- Jet Impingement Heat Transfer – A ReviewIRJET Journal
This document reviews research on jet impingement heat transfer. Jet impingement involves directing a jet of fluid at a surface and is an effective method for transferring heat. It has various industrial applications like cooling electronics and turbine blades. The review examines factors that influence heat transfer like jet geometry, cross flow effects, and frequency. It summarizes studies on single and multiple jet impingement, and the effects of parameters like Reynolds number. Conjugate heat transfer involving solid-fluid interaction is also discussed. The review provides an overview of research conducted on jet impingement heat transfer.
Strategies for the Success of Nuclear Powered Commercial Shippingwww.thiiink.com
ABSTRACT
The development of nuclear powered commercial ships has taken on greater
importance beyond transporting cargo cheaper. Increasing limitations on Sulfur Oxide
emissions from ships has put the global maritime industry on a search for economical
ways to meet current and future environmental regulations. With the inevitable
development of trans-Arctic shipping, nuclear power is the only means of preventing the
phenomenon of “graying of the ice”, which is the deposition of black carbon soot
particles on snow and ice from oil and natural gas burning engines, leading to increased
heat retention and melting. However, unless these next generation nuclear powered
ships are cost-effective and can achieve an acceptable level of safety, they will not be
deployed and their environmental advantages not realized. This paper discusses in
qualitative terms methods for the cost-effective and safe development of nuclear
powered commercial ships for world trade, specifically by a United States initiated
program. Discussed are changes to the nuclear regulatory model that can alleviate
certain economic burdens that ship-sized nuclear reactors may face, and
recommendations are made for how industry can actively lower nuclear power’s high
upfront costs. Emphasis is placed on the development of an inherently safe, widemarket
application reactor that can achieve these cost and safety goals.
This document summarizes a study that used computational fluid dynamics (CFD) to model soil erosion during a hole erosion test (HET). The study used the k-epsilon turbulence model in Fluent software to simulate the biphasic turbulent flow and resulting shear stresses at the water-soil interface. This allowed for a three-dimensional analysis of erosion rates along the hole, unlike typical one-dimensional models. Results showed the inlet side of the hole experienced more erosion than the outlet side due to non-uniform shear stresses. The model aims to better understand and predict piping failures in hydraulic structures by quantifying the effects of flow velocity on erosion rates.
This document summarizes gaseous emission control technologies and cyclone separators. It discusses two approaches to controlling air pollution: pollution prevention at the source and treatment of fumes as they form. Cyclone separators are described as inexpensive devices with no moving parts that are widely used to remove particles from air streams. The document provides details on cyclone design, operation, advantages, disadvantages, and equations for calculating collection efficiency based on factors like particle size, gas velocity, and cyclone dimensions. An example calculation is included to demonstrate determining the collection efficiency of a conventional cyclone for a given particle size distribution.
On The Form Factor Prediction Of A Displacement Type Vessel: JBC CaseIsmail Topal
This document summarizes a study on predicting the form factor of a displacement type vessel (JBC hull) using computational fluid dynamics (CFD). Single-phase CFD simulations were performed for the JBC hull at various velocities within the Prohaska range. The form factor, which represents the ratio of viscous pressure force to frictional force, was calculated from the simulations and found to depend on Reynolds number, contrary to Prohaska's theory of independence. Frictional force results matched well with empirical ITTC formulas. The study aims to further investigate scale effects on form factor prediction.
This document summarizes a study on predicting the form factor of a ship hull through computational fluid dynamics simulations. Researchers conducted single-phase CFD simulations of flow around a Japanese Bulk Carrier hull model at various velocities within the Prohaska range. They evaluated mesh dependency, calculated friction coefficients compared to empirical data, and analyzed the effect of Reynolds number on predicted form factors. The study found that the form factor depends on ship velocity, contrary to Prohaska's theory, and suggests further investigation of scale effects on form factor predictions.
1) The document discusses using computational fluid dynamics (CFD) modeling to design electrostatic precipitators (ESPs) for industrial applications in a multidisciplinary approach.
2) The design procedure involves drafting a design based on specifications, simulating gas flow and particle capture, and modifying the design as needed to meet efficiency specifications.
3) The CFD modeling approach involves time-dependent simulation of gas flow, electric fields, particle charging and migration, collection, and reentrainment to optimize ESP performance.
This 3 sentence summary provides the key details from the document:
The document describes an analytic model for pressurization and cryogenic propellant conditions in liquid rocket tanks. The model divides tanks into 5 nodes and solves conservation equations of mass and energy across the nodes. It can model various mass transfer mechanisms and has been validated against test data. The model provides tank conditions like pressure and temperatures over mission durations for design and analysis of cryogenic rocket stages.
An analysis of the Lattice Boltzmann Method (LBM) has been developed as an alternating Computational Fluid Dynamic (CFD) method based on the collective behavior of microscopic particles. This numerical method contrasts
with the traditional approaches which usually consider macroscopic descriptions by using Navier-Stokes (NS) equations.The specific purpose of the present thesis is to supply a comprehensive description of the field providing a source code for practical applications under GNU copyright.
In the first part the review of the fundamental macroscopic variables is emphasized to outline the NS equations with advantages and drawbacks.
Numerical methods are investigated in the second part, evolving from Cellular Automata, the most recent Lattice Gas Cellular Automata and specially its extension, the LBM.
The last part of this thesis shows the results of the method comparing to a traditional Navier-Stokes solver. It is also pointed out the advantages adopted with LBM approach in nano-scale multiphase fluid flow under complex boundary conditions.
The cutting-edge applications that the engineers are bringing with using finite element procedure for the human civilization and the emergence of new techniques in solving real-life scenarios in finite element procedures.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
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This document summarizes a computational fluid dynamics (CFD) study of combustion and mixing in a scramjet combustor. The study uses ANSYS Fluent software to model flow inside a scramjet combustor geometry for hydrogen, diesel, and methane fuels. The objectives are to determine the flow field and maximize thrust at a Mach number of 2. Key findings include that combustion increases recirculation behind the flameholder strut compared to mixing alone, and shockwaves from the strut facilitate combustion ignition in regions with fuel-air mixing. Meshing of the combustor geometry and strut are discussed.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
The document discusses rocket engine design and performance. It covers ideal rocket equations and assumptions, the basic components of a rocket including the combustion chamber and de Laval nozzle. Key performance parameters like characteristic velocity, thrust coefficient, and effective exhaust velocity are defined. The relationships between chamber pressure, temperature, nozzle expansion ratio and these velocities are explained. Mixture ratio and its effect on specific impulse is also discussed for liquid oxygen and liquid hydrogen propellants.
ENHANCEMENT OF THERMAL EFFICIENCY OF NANOFLUID FLOWS IN A FLAT SOLAR COLLECTO...Barhm Mohamad
Flat plate solar collector (FPSC) is popular for their low cost, simplicity, and ease of installation and operation. In this work, FPSC thermal performance was analyzed. It's compared to diamond/H2O nanofluids. The volume percentage and kind of nanoparticles are analyzed numerically that validation with experimental data available in the literature. The hot climate of Iraq is employed to approximate the model. The numerical study is performed by using ANSYS/FLUENT software to simulate the case study of problem. Due to less solar intensity after midday, temperatures reduction. The greatest collector thermal efficiency is 68.90% with 1% ND/water nanofluid, a 12.2% increase over pure water. The efficiency of 1% nanofluid is better than other concentrations because of a change in physical properties and an increase in thermal conductivity. Since the intensity of radiation affects the outlet temperature from the solar collector and there is a direct link between them, this increases the efficiency of the solar collector, especially around 12:30 pm at the optimum efficiency.
Investigating the implications of a new-build hybrid power system for RoRo ca...Janie Ling Chin
This document summarizes a study that used life cycle assessment to evaluate the environmental impacts of a proposed hybrid power system for roll-on/roll-off cargo ships from manufacturing to end of life, compared to a conventional power system. The study estimated resource usage, emissions, and impacts and identified operating diesel generators and disposing of metallic scrap as particularly significant processes. It verified the environmental benefits of the hybrid system in most impact categories.
The UCLA Rocket Project has continued developing its custom hybrid rocket engine called HyPE for the 6th Intercollegiate Rocket Engineering Competition. The HyPE uses paraffin wax and aluminum powder fuel with nitrous oxide oxidizer, and is capable of propelling a 10 pound payload to 25,000 feet. Students designed and built a carbon fiber airframe, recovery system, avionics, and ground support equipment. Aerodynamic analysis was performed to optimize the rocket's drag, and a 4.5:1 LD Haack nose cone was selected to reduce wave drag at supersonic speeds. The project involves over 30 students and aims to compete in and win the advanced category of IREC.
This document describes a numerical simulation of magnetohydrodynamic instabilities in nuclear fusion plasma. The simulation analyzed plasma characteristics like magnetic compression and tension. It found that strong initial internal and external magnetic fields can correct for natural MHD instabilities, increasing magnetic confinement time. The best configuration applied a poloidal field of similar magnitude to the toroidal field and a constant external vertical field, increasing confinement time by 400%.
This document discusses atmospheric chemistry models and their use in quantifying atmospheric concentrations and fluxes. Global 3D models divide the atmosphere into grid boxes and use the continuity equation to track species concentrations over time, accounting for transport, chemistry, emissions and deposition. Transport is parameterized using turbulence and convection schemes. Chemistry is solved using operator splitting and implicit methods. Models are evaluated and improved using atmospheric observations from satellites, aircraft and surface sites through data assimilation techniques like inverse modeling. Examples are given of various applications of the GEOS-CHEM global model.
This document discusses the design and analysis of an airborne radome. It begins with an abstract that outlines the purpose of radomes to protect microwave subsystems from environmental effects while maintaining electromagnetic transparency. It then provides a table of contents and overview of the various chapters that will analyze radome design using Creo and ANSYS software, composite materials testing and analysis, and structural analysis including dynamic analysis and pressure testing. The document focuses on the design, analysis, and testing of a composite material radome.
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This document summarizes a joint session between Korean and Japanese organizations on developing optimal routing for smart ships based on real voyage data. It discusses challenges in autonomous vessel technology including route optimization. A case study was presented on estimating fuel consumption for a container ship voyage from Yokohama to San Francisco using modeled resistance calculations calibrated to real voyage data. The optimal route reduced fuel consumption by 4% compared to the great circle route. The session concluded autonomous vessels are becoming reality sooner than expected due to increasing collaboration between industries and researchers.
IRJET- Jet Impingement Heat Transfer – A ReviewIRJET Journal
This document reviews research on jet impingement heat transfer. Jet impingement involves directing a jet of fluid at a surface and is an effective method for transferring heat. It has various industrial applications like cooling electronics and turbine blades. The review examines factors that influence heat transfer like jet geometry, cross flow effects, and frequency. It summarizes studies on single and multiple jet impingement, and the effects of parameters like Reynolds number. Conjugate heat transfer involving solid-fluid interaction is also discussed. The review provides an overview of research conducted on jet impingement heat transfer.
Strategies for the Success of Nuclear Powered Commercial Shippingwww.thiiink.com
ABSTRACT
The development of nuclear powered commercial ships has taken on greater
importance beyond transporting cargo cheaper. Increasing limitations on Sulfur Oxide
emissions from ships has put the global maritime industry on a search for economical
ways to meet current and future environmental regulations. With the inevitable
development of trans-Arctic shipping, nuclear power is the only means of preventing the
phenomenon of “graying of the ice”, which is the deposition of black carbon soot
particles on snow and ice from oil and natural gas burning engines, leading to increased
heat retention and melting. However, unless these next generation nuclear powered
ships are cost-effective and can achieve an acceptable level of safety, they will not be
deployed and their environmental advantages not realized. This paper discusses in
qualitative terms methods for the cost-effective and safe development of nuclear
powered commercial ships for world trade, specifically by a United States initiated
program. Discussed are changes to the nuclear regulatory model that can alleviate
certain economic burdens that ship-sized nuclear reactors may face, and
recommendations are made for how industry can actively lower nuclear power’s high
upfront costs. Emphasis is placed on the development of an inherently safe, widemarket
application reactor that can achieve these cost and safety goals.
This document summarizes a study that used computational fluid dynamics (CFD) to model soil erosion during a hole erosion test (HET). The study used the k-epsilon turbulence model in Fluent software to simulate the biphasic turbulent flow and resulting shear stresses at the water-soil interface. This allowed for a three-dimensional analysis of erosion rates along the hole, unlike typical one-dimensional models. Results showed the inlet side of the hole experienced more erosion than the outlet side due to non-uniform shear stresses. The model aims to better understand and predict piping failures in hydraulic structures by quantifying the effects of flow velocity on erosion rates.
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This document summarizes a study on predicting the form factor of a ship hull through computational fluid dynamics simulations. Researchers conducted single-phase CFD simulations of flow around a Japanese Bulk Carrier hull model at various velocities within the Prohaska range. They evaluated mesh dependency, calculated friction coefficients compared to empirical data, and analyzed the effect of Reynolds number on predicted form factors. The study found that the form factor depends on ship velocity, contrary to Prohaska's theory, and suggests further investigation of scale effects on form factor predictions.
1) The document discusses using computational fluid dynamics (CFD) modeling to design electrostatic precipitators (ESPs) for industrial applications in a multidisciplinary approach.
2) The design procedure involves drafting a design based on specifications, simulating gas flow and particle capture, and modifying the design as needed to meet efficiency specifications.
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This 3 sentence summary provides the key details from the document:
The document describes an analytic model for pressurization and cryogenic propellant conditions in liquid rocket tanks. The model divides tanks into 5 nodes and solves conservation equations of mass and energy across the nodes. It can model various mass transfer mechanisms and has been validated against test data. The model provides tank conditions like pressure and temperatures over mission durations for design and analysis of cryogenic rocket stages.
An analysis of the Lattice Boltzmann Method (LBM) has been developed as an alternating Computational Fluid Dynamic (CFD) method based on the collective behavior of microscopic particles. This numerical method contrasts
with the traditional approaches which usually consider macroscopic descriptions by using Navier-Stokes (NS) equations.The specific purpose of the present thesis is to supply a comprehensive description of the field providing a source code for practical applications under GNU copyright.
In the first part the review of the fundamental macroscopic variables is emphasized to outline the NS equations with advantages and drawbacks.
Numerical methods are investigated in the second part, evolving from Cellular Automata, the most recent Lattice Gas Cellular Automata and specially its extension, the LBM.
The last part of this thesis shows the results of the method comparing to a traditional Navier-Stokes solver. It is also pointed out the advantages adopted with LBM approach in nano-scale multiphase fluid flow under complex boundary conditions.
The cutting-edge applications that the engineers are bringing with using finite element procedure for the human civilization and the emergence of new techniques in solving real-life scenarios in finite element procedures.
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2. 2
5/12/21
All modern launch systems use conventional
solid and/or liquid rocket propulsion systems
High performance
and throttle-able
but
complex, expensive,
explosion hazard.
Liquid Main Engines
Solid Rocket Booster
Mechanically simple
but
difficult to throttle,
expensive, explosion
hazard, environmental
hazard.
There are Increasing concerns about
groundwater contamination by
perchlorates produced in the
manufacture of solid rocket
propellants. Even very low levels of
contamination are correlated with
reduced iodine intake in women.
Worldwide both liquid and
solid rocket propulsion
systems fail at a rate of about
2.5 per 100 launches. The US
failure rate is about 1.5 per
100. No other industry accepts
this rate of failure.
Reference: I-Shih Chang and
Edmardo Joe Tomei of the
Aerospace Corp. AIAA paper
2005-3793
Reference: CDC Report
doi:10.1289/ehp.9466 October 5,
2006. Available at http://dx.doi.org/
3. 5/12/21 3
Gas
Pressurization Liquid Oxidizer
Control
Valve
Motor with fuel grain Nozzle
Igniter
Injector
A hybrid rocket is a design where a liquid oxidizer is vaporized and passed over a solid
fuel.
An igniter is used to evaporate some of the fuel and initiate combustion. Once a flame is
established over the fuel surface the process is self-sustaining.
The hybrid rocket offers an inherently safe, mechanically simple alternative with lower
life cycle costs compared to solids and liquids.
port
Hybrid Rocket System
4. 4
5/12/21
Why hybrids ??
The Challenger disaster - January 28, 1986
Titan 34D-9 SRM failure - April 18, 1986
In the middle of all this was Dave Altman, now almost 100, of
Menlo Park. A member of the Rogers commission, a founder
of CSD and one of the inventors of segmented solid
boosters, Dave is one of the earliest proponents of safer,
cheaper, throttleable hybrids.
t + 0.678sec
t + 59sec
t + 60sec
Dave Altman
Vice pres CSD, Ret.
5. 5
5/12/21
On August 17, 1933, the first liquid rocket launch of the Soviet Union
was a hybrid that used gelled gasoline and liquid oxygen.
9. 9
5/12/21
Some history of hybrids- (1960 - 1985)
• 1960's: Extensive research at various companies.
• Chemical Systems Division of UTC
• Modeling (Altman, Marxman, Ordahl,
Wooldridge, Muzzy etc…)
• Motor testing (up to 40,000 lb thrust level)
• LPC: Lockheed Propulsion Company, SRI: Stanford
Research Institute, ONERA (France)
• 1964-1984: Flight System Development
• Target drone programs by Chemical Systems Division
of UTC
• Sandpiper, HAST, Firebolt
• LEX Sounding Rocket (ONERA, France)
• FLGMOTOR Sounding Rocket (Sweden)
• 1973-1982: Indian Institute of Science 100 kgf motor
• Swirl injection, hypergolic solid fuels with RFNA
• 96% c* efficiency
CSD’s Li/LiH/PBAN-F2/O2 Hybrid
Measured Isp=480 sec
Firebolt Target Drone
10. 10
5/12/21
• 1981-1985: Starstruck Co. launched the Dolphin sounding rocket (35 klb thrust)
• 1985-1995: AMROC continuation of Starstruck
• Tested 10, 33, 75 klb thrust subscale motors.
• Developed and tested the H-1800, a 250 klb LO2/HTPB motor.
• 1990’s: NASA Hybrid Propulsion Development Program (HPDP)
• Developed and tested 250 klb thrust LO2/HTPB motors.
• 2002: Lockheed developed and flight tested a 24 inch LO2/HTPB hybrid sounding rocket (HYSR). (60 klb thrust)
• 2003: Scaled Composites and SpaceDev developed N2O/HTPB hybrid for the sub-orbital vehicle SpaceShipOne.
(20 klb thrust)
• 2013: April 29 First powered flight of Space Ship Two
• 2018: September 27 – Nammo launch of the Nucleus Sounding Rocket over 100km
• 2019: February 22 Virgin Galactic flight of VSS Unity with its first passenger.
SpaceShipOne
Dolphin
AMROC Motor Test
Recent History - (1981 - Present)
VSS Unity
Faenza, M. G.,
Boiron, A.J.,
Haemmerli, B. and
O. Verberne, ”The
Nammo Nucleus
Launch", AIAA
2019-4049, P&E,
Indianapolis, Aug
19, 2019.
12. 12
5/12/21
Turbulent boundary layer combustion
In a hybrid rocket, the fuel surface regression rate is determined by the mass flux in the port.
Constants a and n are empirical values for a given choice of fuel and oxidizer. Typically 0.4 < n < 0.8.
Marxman, G. A., and
Gilbert, M., "Turbulent
Boundary Layer
Combustion in the Hybrid
Rocket", Ninth
Symposium
(International) on
Combustion, The
Combustion Institute, pp.
371-383, 1963.
!
r ≈ aGn G =
!
mport
πr2
=
!
mox + !
mfuel
πr2
In a solid rocket the propellant surface regression rate is determined by the chamber pressure.
!
r = aPn
The constant a, depends on propellant temperature at launch, n < 1 is required to prevent explosion.
r
c
L
13. 13
5/12/21
Hybrid motor gas generation is governed by two coupled, first order semi-impirical PDEs
Fuel surface
regression rate
equation
!
mport = !
mox + !
mf
Port mass flow
growth rate
equation
These equations are
often simplified to !
r = aGox
n
Gox =
!
mox
πr2
This can be used to
roughly characterize a
given motor if the O/F is
not too low.
The dependence on x
arises from a turbulent
boundary layer heat
transfer mechanism.
14. 14
5/12/21
• The empirical constants a, n and m hide a variety of physical processes
that affect the fuel regression rate and need to be taken into account in
a given motor design. This includes
! Radiative heat transfer
! pyrolysis
! two phase flow
! turbulent and transitional flow
! injector geometry, swirl
! Motor/port geometry and size
• The potential benefits of hybrids together with the complex multi-physics
nature of hybrid rocket combustion make the subject an important area
for both fundamental and applied research.
• Some good review sources,
D. Altman, A. Holzman, Overview and history of hybrid rocket propulsion, in: K. Kuo, M. Chiaverini (Eds.),
Fundamentals of Hybrid Rocket Combustion and Propulsion, Vol. 218 of Progress in Astronautics and
Aeronautics, AIAA, 2007, pp. 1–36.
Chemical Rocket Propulsion: A Comprehensive Survey of Energetic Materials, Part VI Hybrid Rocket
Propulsion. L. De Luca, T. Shimada, V.P. Sinditskii, M. Calabro (Editors), Springer Aerospace Technology, 2017.
H. S. Mukunda, V.K. Jain, and P.J. Paul, “A review of hybrid rockets: present status and future potential”, Proc.
Indian Acad. Sci., Vol C 2, part 1, May 1979, pp. 215-242.
16. 5/12/21 16
The fuel regression rate law
Hybrid combustion is governed by two coupled first order PDEs
Fuel surface regression rate
equation
!
mport = !
mox + !
mf
Port mass flow growth rate
equation
The port mass flux is generally denoted by G.
The constants a, n and m are empirical values for a given choice of fuel
and oxidizer. Typically m is very small and 0.4 < n < 0.7.
17. 5/12/21 17
The units of the regression rate constant a
r =
a
xm
Gn
L
T
=
a
[ ]
Lm
M
L2
T
⎛
⎝
⎜
⎞
⎠
⎟
n
a
[ ]=
L2n+m+1
T1−n
M n
[ ]= units of
a = 0.0488
cm2n+m+1
sec1−n
gmn
⎛
⎝
⎜
⎞
⎠
⎟ = 0.0488
0.01m
( )2n+m+1
sec1−n
0.001kg
( )n
⎛
⎝
⎜
⎞
⎠
⎟ = 0.0488
0.01
( )2n+m+1
0.001
( )n
⎛
⎝
⎜
⎞
⎠
⎟
m2n+m+1
sec1−n
kgn
⎛
⎝
⎜
⎞
⎠
⎟
n = 0.62
m = 0
a = 0.0488
cm2.24
sec0.48
gm0.62
⎛
⎝
⎜
⎞
⎠
⎟ = 0.0488
0.01
( )2.24
0.001
( )0.62
⎛
⎝
⎜
⎞
⎠
⎟
m2.24
sec0.48
kg0.62
⎛
⎝
⎜
⎞
⎠
⎟ =1.17063×10−4 m2.24
sec0.48
kg0.62
⎛
⎝
⎜
⎞
⎠
⎟
Unit conversion cgs to mks
18. 5/12/21 18
Separate variables.
πn
ao
r2n
dr = !
mox t
( )
( )
n
dt
Integrate
In this approximation the radius at any moment is constant along the port. This
assumption underpredicts the fuel generation rate and is not an accurate predictor
of the O/F ratio at the end of the port especially for low O/F ratios.
Simplified approach - A simplification that is often used is to assume the
regression rate only depends on the oxidizer mass flux.
Regression rate analysis
19. 5/12/21 19
The basic regression rate law can be put into the form of the
simplified relation using the definition of the O/F ratio.
The problem with ao
O / F = !
mox / !
mf
The “constant” ao actually depends on time and space.
20. 5/12/21 20
The regression rate equation is
The mass flow rate increase along the port is determined by the rate at
which mass is swept up from the fuel surface.
These first order PDEs need to be solved simultaneously for the local mass
flow rate and port radius.
Solve the nonlinear coupled mass-flow-regression-rate problem
mport =
mox +
mf
∂r x,t
( )
∂t
= a
mport
( )
n
π n
xm
r2n
21. 5/12/21 21
The coupled problem can be solved exactly for the case .
n = 1/ 2
The increase in port surface area exactly balances the decrease in mass flux
and so the mass flow rate is constant with time for constant oxidizer mass flow
rate. The O/F at the end of the port is constant.
The case n=1/2
26. 5/12/21 26
Example - 100 second burn time
Numerical solution
captures the “coning”
effect due to the mass
flow increase in the port
as well as the port
minimum due to a nonzero
m exponent on x.
n = 0.62
m = 0.015
a = 9.27 ×10−5
m2.39
kg−0.62
sec−0.38
!
mox = 4.43kg /sec
28. 28
5/12/21
Classical Hybrids
Low burning rates
of polymeric fuels
require a multi-port
design
The hybrid design concept has been known for more than 85 years.
Small hybrid rocket motors built to military specifications were used in target drone programs
between 1968 and 1983 (Sandpiper, Hast, Firebolt). Eventually Space Ship Two will begin to
take tourists to the edge of space.
Yet, despite this experience, the hybrid has never been developed to power large launch
systems capable of taking a payload to orbit. Why?
29. 5/12/21 29
Disadvantage of Classical Hybrids
Classical polymeric
fuels such as HTPB
are impractical for
a launch system
due to low
volumetric loading,
poor fuel grain
structural integrity,
large unburned fuel
sliver
Low burning rates
of polymeric fuels
require a multi-port
design
The hybrid design concept has been known for more than 50 years.
Small Hybrid rocket motors built to military specifications were used in target drone
programs between 1968 and 1983 (Sandpiper, Hast, Firebolt). The fuel used was
Hydroxyl-Terminated-Polybutadiene (HTPB).
Yet, despite this experience and clear advantages, the hybrid has never been
developed to power large launch systems capable of taking a payload to orbit. Why?
In the early 1990’s
AMROC was founded to
develop commercial
hybrids. They tested
large 250klbs thrust
motors. Venture failed in
the late 90’s.
Lockheed Martin
Michoud worked on
developing a 42 port
HTPB motor for use in
the AF FALCON
program.
31. 31
5/12/21
Approaches to High Regression Rate
Technique Fundamental
Principle
Shortcoming
Add oxidizing agents
self-decomposing
materials
Increase heat transfer
by introducing
surface reactions
• Reduced safety
• Pressure
dependency
Add metal particles
(micron-sized)
Increased radiative
heat transfer
• Limited
improvement
• Pressure
dependency
Add metal particles
(nano-sized)
Increased radiative
heat transfer
• High cost
• Tricky processing
Use Swirl Injection Increased local mass
flux
• Increased
complexity
• Scaling?
All based on
increasing
heat transfer
to the fuel
surface.
32. 32
5/12/21
• Solid propellant is a frozen material
• Motivation:
• Performance Benefit: More flexibility on propellant
selection (eg. H2 & O2).
• AFRL at Edwards AFB
• Solid Pentane @ 77 K.
• 3-5 fold increase in the regression rate for pentane.
Solid Cryogenic Hybrids - Air Force (AFRL) Tests
Larson, C. W., Pfeil, K. L., DeRose, M. E., and Carric, P. G., “High Pressure Combustion
of Cryogenic Solid Fuels for Hybrid Rockets,” AIAA Paper 96-2594, July 1996.
The Air Force shared their experimental data with us.
33. 5/12/21 33
In his PhD research, Arif Karabeyoglu was able to model the high pentane mass transfer rates observed by the AFRL researchers and showed that:
1) Pentane forms a thin melt layer on the fuel surface.
2) The layer is linearly unstable under the shear by the gas flow in the port and blowing from the fuel surface.
3) Results from the Nuclear Safety literature can be used to include nonlinear growth and droplet entrainment in classical hybrid theory.
Conclusion - Total fuel mass transfer rate is increased by a factor of 3 to 4.
Entrainment Theory - Pentane Predictions
Mass flux - kg / m2
-sec
Regression
rate - mm /sec
AFRL data
34. 34
5/12/21
Thin film instability plus nonlinear growth and wave breaking leads
to entrainment of droplets along the port
ρlUlh
µl
= 100 − 300
Film Reynolds number
ρlVlh
µl
= 0.1−1.0
Liquid blowing Reynolds number
Diffusion
Flame
Entrained
Droplets
Reacting Droplets
Liquid Layer
Fuel Grain
Liquid Layer
Vl
ρeUe
h 50 −100µM
ρs
r = ρlVl
Fuel Grain
A. D. D. Craik, “Wind-generated waves in thin liquid films”, JFM 26, 1966.
Nigmatulin, R.I., Nigmatulin, B.I., Khodzhaev, D., Kroshilin, V.E., ”Entrainment and
Deposition Rates in a Dispersed-Film Flow" Int. J. Multiphase Flow, vol 22, 1996.
Karabeyoglu,
Altman and
Cantwell,
“Combustion of
liquifying hybrid
propellants” parts
1 and 2, J. Prop.
and Power, vol
18, 2002.
T. B. Benjamin, “Shearing flow over a wavy boundary”, JFM 6, 1959.
35. 5/12/21 35
Viscosity of the melt layer increases with alkane molecular weight.
Viscosity of the melt layer decreases with melt layer temperature.
Molecular Weight - gm / mole
Temperature - C
Melt Layer Temperature for CnH2n+2 Series
36. 36
5/12/21
Entrainment for CnH2n+2 Series
Carbon numbers between
25 and 45 are predicted to
burn rapidly
C:
Mw:
1 5 25 45 14,000
16 72 352 632 200,000
Cryogenic Non-cryogenic
Methane
(Tested) Paraffin Waxes
65 80
PE Waxes
HDPE Polymer
(Tested)
912 1262
(g/mol)
Pentane
(Tested)
Gas Liquid Solid Polymer
Mw
Entrainment
Entraiment
Boundary
37. 37
5/12/21
Liquid Layer Hybrid Combustion Theory
• Modify Marxman’s theory to include mass transfer through
droplet entrainment.
• Steps of the Theory Development
• Estimate film thickness
• Stability of the liquid film
• Scaling for the entrainment mass transfer
• Modify “Diffusion Limited Model” for the existence of
entrainment
• Modification of the classical Hybrid Combustion Theory
– Reduced heating requirement for the entrained mass.
– Reduced “Blocking Effect” due to two phase flow.
– Increased heat transfer due to the increased surface roughness.
38. 38
5/12/21
Liquid layer hybrid combustion theory predicts
˙
r"wax" ≈ ˙
rpentane ≈ 3 − 5 × ˙
rclassical
Diagram depicts an 83% fuel
loading design
The high burn rate of paraffin-based fuels leads to a single port
design that makes large hybrids practical.
Fuel loading above 80% is feasible
42. 42
5/12/21
Regression rate data for paraffin-based fuel
Regression
rate - mm /sec
Oxidizer mass flux - kg / m2
-sec
Three fold
improvement
is confirmed
Paraffin-based fuel: 70C Melt Point, Fully Refined Wax (C32H66) + 2% Stearic Acid (C18H36O2) by weight
49. 49
5/12/21
Oxygen compatible combustion visualization tunnel Ashley Karp, Beth Jens
45 cm
20 cm
• Material - Brass
• Chamber pressure: atmospheric up to 17.24 bar
• Windows: 3.81 cm Polycarbonate, later Quartz
• Ignition: Nichrome wire, currently diode laser
The experimental challenge –
directly visualize oxygen-fuel combustion at 3000K up to 2 MPa
51. 5/12/21 51
Combined schlieren and OH* results - Blackened Paraffin 71 psi
Jens, et al.,"Schlieren and OH* chemiluminescence imaging of combustion in a turbulent boundary layer over a solid fuel
" Experiments in Fluids, 57:39, March 2016.
310 nm
54. 5/12/21 54
The largest motor we have built to date is a 15,000 lb class motor for the
Peregrine sounding rocket project led by Greg Zilliac of NASA Ames
90-95% C* efficiency
56. 5/12/21 56
Applications
Launch boosters, small satellite launch
In-space motors
• Orbit changing, planetary exploration
Sub-orbital space flight
• Space tourism - Space Ship One, Space Ship Two
Science and Technology Missions
• Zero gravity experiments
• Sounding rockets - A large number of very low cost solid
systems are available but they restrict the kinds of payloads
that are flown. NASA runs 30 to 40 flights per year
• Planetary exploration
59. 5/12/21 59
Capture/Cont
ainment and
Return
System
(CCRS)
Mars 2020 Earth Return Orbiter Sample Retrieval and Launch Sample Return and Science
Tube Retrieval
Mars Ascent Vehicle
(MAV) Launch
Earth Return
Module (ERM)
Break the Chain
Mars 2020
Orbiting Sample
(OS)
Earth
Mars
Retrieve OS
ERO Divert
Earth Return
Orbiter* (ERO)
Sample Return
Lander (SRL)
Sample Tubes
Mars Returned
Sample Handling
(MRSH) Facility
MSR Mission Architecture
60. 5/12/21 60
The Mars 2020 rover will drill rock samples and place them in individual tubes.
The samples would be left on the surface of Mars for later pick up by a second rover.
The second rover would place the samples in the payload bay of the MAV which
would then launch to Mars orbit.
Orbiting Sample (OS)
61. 5/12/21 61
Mars 2020 landing site was chosen November 2018
Jezero crater - 18° above the
Mars equator
Curiosity rover – Temperature and Pressure at Gale crater on Mars (Aug 2012 to Feb 2013
Gale crater - 5° below the Mars equator
63. 5/12/21 63
A wide temperature range fuel designated SP7 was developed in 2015 by
Space Propulsion Group, Inc.
Thermal cycling representative of 200 Mars sols at Mars pressure was carried out at NASA Marshall
Space Flight Center. Both aluminized and non-aluminized samples were studied.
64. 5/12/21 64
SP7/MON-25 at -20 C
LITVC
Restart
Whittinghill Aerospace
SP7/MON-3
Regression Rate
Space Propulsion Group
MAV Development testing
MON3 and MON25 have a relatively low vapor pressure requiring substanial heat addition at the fore end of
the motor to achieve stability. To address this a low flow of MMH is injected which is hypergolic with MON.
65. 5/12/21 65
Hybrid Motor
MMH tank
LITVC
Nozzle
Liquid Oxidizer
tank
Helium Tanks
Avionics
Package
RCS Thrusters
• Design predicted to close from a propulsion point of
view (GLOM~400 kg, dV=~3900 m/s, fits in the
lander)
• More development work to be done
• No obvious show stoppers
• Testing to demonstrate that the total impulse can
be delivered
• Some analyses need to be finalized to reduce
mass
• Engine shutoff is an important capability
• Additional capability in the RCS system for fine
tuning of orbit
• Motor design is flexible and can be modified as
vehicle matures
• Preliminary thermal, structural, and CFD analysis
results have been incorporated
• Orbit tolerances met in all cases
Hybrid SSTO MAV Design – JPL/MSFC
66. 5/12/21 66
In 2018 the decision was made to to provide a
thermal control system (igloo) for the MAV
High Technology Readiness Level (TRL) Thermal control system
components are used to maintain MAV operating (-20C) and non-
operating (-40C to +40C) temperatures for all stages of flight.
67. 5/12/21 67
MAV Decision late 2019
• Benefits of the hybrid option include its predicted low temperature behavior, high performance
and ability to restart (enabling the SSTO).
• MAV 2015 Study concluded that for MAV low temperature requirements, hybrids had
advantages. However TRL was low and a plan was made to develop the technology to be
ready to compete for > 2030 launch.
• In 2018, the launch window was moved up to 2026, shortening technology development time
for the hybrid.
• In 2018 decision was made to use an igloo to provide thermal control of the MAV while on the
Mars surface. This increased launch temperature requirement from -50C to -20C.
• Solid option has a high TRL level. Studies are currently underway to determine if the solid can
meet orbital dispersion requirements.
• Downselect between the two options occurred in late 2019 – two stage solid was selected.
69. 5/12/21 69
Two Stage Solid MAV Design – JPL/MSFC
• Solid propulsion TRL is high with a legacy of
use on Mars.
• Vehicle Gross Lift-Off Mass (GLOM),
temperature extremes, and orbital dispersions
are the most significant challenges
• Mission design includes two burns separated by
a long coast
o Stage 1 puts the vehicle into a highly
elliptical orbit with an apoapsis at the desired
altitude of the circular orbit, but with a
negative periapsis.
o Once the vehicle has coasted nearly to
apogee, Stage 2 fires to circularize the orbit
• RCS must conduct control maneuvers during
the long coast between stages.
• Orbital dispersion currently under study