This study examined the mass transport phenomena associated with evaporation through experimental and analytical techniques. Gravimetric analysis, shadowgraph imaging, and IR spectral analysis were used to measure vapor concentration data for methanol, hexane, and 3-methylpentane evaporating from a surface. The concentration data was modeled using Gridfit to compute concentration gradients and diffusion rates within control volumes. Diffusion rates were compared to theoretical values, revealing evidence of additional convection transport mechanisms. The methodology provides insights into evaporation applications like coating, spray cooling, and surface patterning.
Este documento describe la evolución nacional e internacional de la higiene y seguridad laboral en el marco legal. A nivel nacional, la seguridad industrial en Venezuela comenzó en 1909 con la ley de minas y la legislación se desarrolló más en 1936 y 1944. Actualmente se rige por la LOPCYMAT. A nivel internacional, la preocupación por el bienestar laboral data de 400 aC, mientras que las primeras leyes importantes fueron la Ley de Fábricas de 1833 en el Reino Unido y la Ley de Seguridad e Higi
This document appears to be an exam for a transport phenomena course, consisting of 16 multi-part questions testing various concepts. The questions cover topics like fluid flow systems, the Navier-Stokes equations, non-Newtonian fluid models, dimensionless numbers, fluid mechanics calculations, heat and mass transfer analogies, turbulence, and more. The exam is divided into two parts, with Part A consisting of 10 short answer questions worth 4 marks each, and Part B consisting of 4 longer answer questions worth 15 marks each.
This document provides a detailed table of contents for a course on transport phenomena. It outlines topics related to momentum transport and fluid dynamics including the equation of continuity, viscous stress, and momentum balances. It also covers mass transfer in reactive and non-reactive systems, including diffusion, mass transfer coefficients, and applications to reactors. Finally, it provides an overview of the first lecture which defines vectors, fluxes, and derives the equation of continuity for incompressible fluids.
Este documento describe los conceptos y características de los sistemas operativos distribuidos y centralizados. Explica que los sistemas operativos distribuidos permiten la ejecución concurrente de procesos en múltiples nodos de computación a través de una red, mientras que los sistemas centralizados usan los recursos de una sola computadora. También discute las ventajas y desventajas de ambos modelos, así como conceptos como el modelo cliente-servidor y la arquitectura de múltiples capas.
This document contains three problems related to transport phenomena:
1. Determining velocity components for a 2D steady flow given one velocity, and conditions for irrotational and satisfying Navier-Stokes equations.
2. Calculating the steady-state interface height of a liquid in a rotating container, assuming rigid body rotation and neglecting surface tension.
3. Analyzing start-up flow between a suddenly moving flat plate and initially stationary fluid, reducing the Navier-Stokes equation to ordinary differential equation and solving for velocity profile over time.
This document provides an overview of a Polymer Reaction Engineering course. The course goals are to introduce students to reaction engineering, polymerization reactions, kinetics, and reactor design. The course objectives are for students to understand reaction kinetics and apply this to the conceptual design of reactors. The schedule outlines 16 weeks of topics like batch and continuous reactor design, polymerization reactions, and a final design project.
This document provides a summary of a textbook on chemical engineering principles and calculations. It was written by David M. Himmelblau and James B. Riggs, and is now in its 7th edition. The textbook covers topics such as material balances, energy balances, thermodynamics, and other core chemical engineering concepts. It aims to explain principles in a clear, readable manner while also developing problem-solving skills. The intended audience is undergraduate chemical engineering students, though it may also be useful for related courses and independent study.
Chemical Reaction Engineering (CRE) studies chemical reaction rates and mechanisms and reactor design. It is important for many industries like chemicals, pharmaceuticals, and medicine. The document discusses mole balance equations for batch reactors, continuously stirred-tank reactors (CSTR), plug flow reactors (PFR), and packed bed reactors (PBR). It also covers reaction rates and examples.
Este documento describe la evolución nacional e internacional de la higiene y seguridad laboral en el marco legal. A nivel nacional, la seguridad industrial en Venezuela comenzó en 1909 con la ley de minas y la legislación se desarrolló más en 1936 y 1944. Actualmente se rige por la LOPCYMAT. A nivel internacional, la preocupación por el bienestar laboral data de 400 aC, mientras que las primeras leyes importantes fueron la Ley de Fábricas de 1833 en el Reino Unido y la Ley de Seguridad e Higi
This document appears to be an exam for a transport phenomena course, consisting of 16 multi-part questions testing various concepts. The questions cover topics like fluid flow systems, the Navier-Stokes equations, non-Newtonian fluid models, dimensionless numbers, fluid mechanics calculations, heat and mass transfer analogies, turbulence, and more. The exam is divided into two parts, with Part A consisting of 10 short answer questions worth 4 marks each, and Part B consisting of 4 longer answer questions worth 15 marks each.
This document provides a detailed table of contents for a course on transport phenomena. It outlines topics related to momentum transport and fluid dynamics including the equation of continuity, viscous stress, and momentum balances. It also covers mass transfer in reactive and non-reactive systems, including diffusion, mass transfer coefficients, and applications to reactors. Finally, it provides an overview of the first lecture which defines vectors, fluxes, and derives the equation of continuity for incompressible fluids.
Este documento describe los conceptos y características de los sistemas operativos distribuidos y centralizados. Explica que los sistemas operativos distribuidos permiten la ejecución concurrente de procesos en múltiples nodos de computación a través de una red, mientras que los sistemas centralizados usan los recursos de una sola computadora. También discute las ventajas y desventajas de ambos modelos, así como conceptos como el modelo cliente-servidor y la arquitectura de múltiples capas.
This document contains three problems related to transport phenomena:
1. Determining velocity components for a 2D steady flow given one velocity, and conditions for irrotational and satisfying Navier-Stokes equations.
2. Calculating the steady-state interface height of a liquid in a rotating container, assuming rigid body rotation and neglecting surface tension.
3. Analyzing start-up flow between a suddenly moving flat plate and initially stationary fluid, reducing the Navier-Stokes equation to ordinary differential equation and solving for velocity profile over time.
This document provides an overview of a Polymer Reaction Engineering course. The course goals are to introduce students to reaction engineering, polymerization reactions, kinetics, and reactor design. The course objectives are for students to understand reaction kinetics and apply this to the conceptual design of reactors. The schedule outlines 16 weeks of topics like batch and continuous reactor design, polymerization reactions, and a final design project.
This document provides a summary of a textbook on chemical engineering principles and calculations. It was written by David M. Himmelblau and James B. Riggs, and is now in its 7th edition. The textbook covers topics such as material balances, energy balances, thermodynamics, and other core chemical engineering concepts. It aims to explain principles in a clear, readable manner while also developing problem-solving skills. The intended audience is undergraduate chemical engineering students, though it may also be useful for related courses and independent study.
Chemical Reaction Engineering (CRE) studies chemical reaction rates and mechanisms and reactor design. It is important for many industries like chemicals, pharmaceuticals, and medicine. The document discusses mole balance equations for batch reactors, continuously stirred-tank reactors (CSTR), plug flow reactors (PFR), and packed bed reactors (PBR). It also covers reaction rates and examples.
This document summarizes research on modeling the dynamic viscoelastic fracture of elastomers. Experiments were conducted to measure crack speeds in polyurethane specimens under different stretching levels. A hyperelastic model alone could not capture transonic crack speeds observed. Including finite linear viscoelasticity in the model, calibrated using DIC and DMA data, better matched experimental results. Finally, a rate-dependent cohesive zone model linked to the viscoelastic bulk model was able to predict the trend in crack speed versus applied stretch seen in experiments.
Analytical ultracentrifugation (AUC) is a technique that uses centrifugation and optical detection systems to study macromolecules in solution. It can determine properties like molecular mass, shape, interactions and conformational changes. AUC instruments spin samples at high speeds and use detectors like absorbance or fluorescence to monitor sedimentation and calculate properties. Common experiments are sedimentation velocity, which determines size and shape, and sedimentation equilibrium, which determines molecular mass and interactions. AUC has applications in characterizing proteins, nucleic acids, viruses and other biological complexes.
Analytical centrifugation is a technique used to characterize macromolecules based on how they sediment in a centrifugal field. The document discusses the instrumentation, working principle, and two main types of analysis - sedimentation velocity and sedimentation equilibrium. Sedimentation velocity provides information about shape, mass, and size by monitoring the boundary formed over time as particles sediment. Sedimentation equilibrium determines mass composition by analyzing the particle distribution once equilibrium between sedimentation and diffusion is reached. Analytical centrifugation is useful for determining properties like molecular weight, stoichiometry, assembly, and conformation.
The document summarizes research related to computational imaging being conducted by the Imaging Concepts group led by Prof. Andy Harvey at the University of Glasgow. Specific areas discussed include:
- Developing low-cost infrared camera array systems using computational techniques as an alternative to more complex optical setups.
- Applying techniques like synthetic aperture, light field imaging, temporal interpolation and pixel super-resolution to camera arrays.
- Demonstrating snapshot pixel super-resolution and integral imaging using a 5x5 camera array to produce higher resolution images.
- Developing a low-cost multispectral LWIR system using 6 FLIR LEPTON cameras and filters to enable applications like gas detection and classification
This document describes the validation of a high throughput electrochemical gas sensing screening system. Uniform thin film samples of YSZ and WO3 were developed and characterization using reflectometry and XRD confirmed their relative uniformity. Single and multielectrode cell tests were conducted on the samples at 600°C, showing their ability to detect different concentrations of NO gas. The system was able to conduct combinatorial screening of electrochemical gas sensors and validate the use of a planar sensor array design. Future work involves further optimizing the system.
ACEMD: High-throughput Molecular Dynamics with NVIDIA Kepler GPUsCan Ozdoruk
Acellera Founder Gianni De Fabritiis, and CTO Matt Harvey talk about the latest developments of high-throughput molecular dynamics both in terms of applications and methodological advances. Examples are in the context of ACEMD, a highly efficient, best-in-class graphical processing units (GPUs) centric code for running MD simulations, and its protocols. In particular, attendees will learn how the high arithmetic performance and intrinsic parallelism of the latest NVIDIA Kepler GPUs can offer a technological edge for molecular dynamics simulations. Try GPUs for free via: www.Nvidia.com/GPUTestDrive
The document summarizes a student project that developed a control strategy to test the capacity and efficiency aging of a domestic lithium-ion battery energy storage system (BESS). The project identified models of BESS operation and aging, an effective test methodology, designed and implemented a control system, and tested a BESS unit using the system. Key results showed an average capacity degradation of 0.16% per cycle and efficiency degradation of 0.07% per cycle over 15 cycles. The control strategy and testing approach can be applied to other BESS units for comparison.
This document summarizes research on applying principles from nature to architectural design. It explores concepts like lightness, emergence, and animal architecture found in nature. The research analyzed structural elements from living systems and how to design complex emergent structures from simple elements, similar to biological systems. The goal is to create designs that use less mass and energy through techniques like form-finding and understanding how an organism's properties depend on its growth and environment. The research aims to apply these natural principles to the design of the W.E.F.T. system through digital technologies and fabrication methods.
Bubble columns are widely used in the chemical and biochemical process industries. In order to develop design tools for engineering purposes, a large amount of research has been carried out in the area of CFD of gas-liquid flows. In this paper a transient Euler-Lagrange solver developed using the open source Caelus library is used to simulate the gas-liquid flow in a 3D square cross-sectioned bubble column. The turbulence is modelled using large eddy simulation (LES). The results of the simulations are compared to published PIV measurements. It is found that, good quantitative agreement with experimental data is obtained when drag, lift and virtual mass forces are used.
1) The document presents a study investigating the effect of microporosity on the longitudinal dispersion coefficient in porous media.
2) It develops an algorithm to simulate solute particle transport through porous media considering both advection and diffusion movements, as well as microporosity.
3) The results show that including microporosity increases the longitudinal dispersion coefficient, especially at higher Peclet numbers, with increases of up to 50% observed. This indicates microporosity has a significant impact on transport and has often been ignored in simulations.
An Autocorrelation Analysis Approach to Detecting Land Cover Change using Hyp...grssieee
The document presents an approach to detecting land cover change using temporal autocorrelation analysis of hyper-temporal satellite imagery. The methodology develops an autocorrelation-based change metric to distinguish real changes from natural phenological cycles. The optimal autocorrelation lag and detection threshold are determined using simulated change datasets. When applied to MODIS imagery of settlements in Gauteng, South Africa, the approach detected over 92% of real changes with an overall accuracy of 88%.
This study developed computational models to simulate the diffusion of vascular endothelial growth factor (VEGF) from hydrogel sources in a microfluidic device over 24 hours. A 2D stationary model, 1D time-dependent model, and 2D transient model were created in COMSOL to predict the VEGF gradient strength and diffusion distance over time. Sodium alginate and heparin-alginate hydrogels were also tested for sustained VEGF release by measuring protein concentration changes. The transient model predicted that the peak gradient strength would occur at 5 hours and that most VEGF would diffuse within 8 hours. Future work will use the heparin-alginate gels in cell migration assays to study how the VEGF gradient enhances
Master Thesis Presentation: Numerical Simulation of Modelled Blood Cells in a...Jesus Alvarez Sarro
This document summarizes a master's thesis presentation on numerically simulating modeled blood cells in viscous flow. The presentation includes sections on introduction, methodology, hydrodynamic effects, simulations with spheres and ellipsoids, and discussion. It describes grid generation studies, analysis of drag and lift forces on particles, velocity profiles, and the influence of particle concentration on focusing. Simulation results for spheres show they focus in two locations further downstream than experiments. Preliminary simulations with ellipsoids show only slight focusing, agreeing with experiments.
The document describes a study on the effect of holes on the tensile strength of composite materials created through hand layup. It outlines the goals to develop a hand layup procedure and test how holes influence composite strength. The methodology section explains the hand layup process and sample preparation/testing. Results show the material's properties are lower than expected and holes reduce strength. The characteristic length, over which stresses average around a hole, is calculated to be approximately 0.133 inches.
In this work, the synthetic Hydroxyapatite (HAP)
was studied using different preparation routes to
decrease the crystal size and was studied the
temperature effect on the nano-sized hydroxyapatite
crystallization. X-ray diffraction (XRD) analysis
indicated the all samples were composed by a
crystalline HAP phase and another amorphous part.
This paper applies inverse transform sampling to sample training points for surrogate models. Inverse transform sampling uniformly generates a sequence of real numbers ranging from 0 to 1 as the probabilities at sample points. The coordinates of the sample points are evaluated using the inverse functions of Cumulative Distribution Functions (CDF). The inputs to surrogate models are assumed to be independent random variables. The sample points obtained by inverse transform sampling can effectively represent the frequency of occurrence of the inputs. The distributions of inputs to the surrogate models are fitted to their observed data. These distributions are used for inverse transform sampling. The sample points have larger densities in the regions where the Probability Density Functions (PDF) are higher. This sampling approach ensures that the regions with higher densities of sample points are more prevalent in the observations of the random variables. Inverse transform sampling is applied to the development of surrogate models for window performance evaluation. The distributions of the following three climatic conditions are fitted: (i) the outside temperature, (ii) the wind speed, and (iii) the solar radiation. The sample climatic conditions obtained by the inverse transform sampling are used as training points to evaluate the heat transfer through a generic triple pane window. Using the simulation results at the sample points, surrogate models are developed to represent the heat transfer through the window as a function of the climatic conditions. It is observed that surrogate models developed using the inverse transform sampling can provide higher accuracy than that developed using the Sobol sequence directly for the window performance evaluation.
The document describes research into creating variable modulus hydrogels through a diffusion cycling process to fabricate multi-network gels with increasing mechanical strength and decreasing swelling ratio for use as tissue scaffolds. Experiments showed compressive and shear modulus increased over 3 diffusion cycles while gel fraction plateaued, indicating potential for tailoring hydrogel properties. Future work aims to further optimize mechanical properties and evaluate gels for regenerative medicine applications like 3D bioprinting of tissues.
This document summarizes research on modeling the dynamic viscoelastic fracture of elastomers. Experiments were conducted to measure crack speeds in polyurethane specimens under different stretching levels. A hyperelastic model alone could not capture transonic crack speeds observed. Including finite linear viscoelasticity in the model, calibrated using DIC and DMA data, better matched experimental results. Finally, a rate-dependent cohesive zone model linked to the viscoelastic bulk model was able to predict the trend in crack speed versus applied stretch seen in experiments.
Analytical ultracentrifugation (AUC) is a technique that uses centrifugation and optical detection systems to study macromolecules in solution. It can determine properties like molecular mass, shape, interactions and conformational changes. AUC instruments spin samples at high speeds and use detectors like absorbance or fluorescence to monitor sedimentation and calculate properties. Common experiments are sedimentation velocity, which determines size and shape, and sedimentation equilibrium, which determines molecular mass and interactions. AUC has applications in characterizing proteins, nucleic acids, viruses and other biological complexes.
Analytical centrifugation is a technique used to characterize macromolecules based on how they sediment in a centrifugal field. The document discusses the instrumentation, working principle, and two main types of analysis - sedimentation velocity and sedimentation equilibrium. Sedimentation velocity provides information about shape, mass, and size by monitoring the boundary formed over time as particles sediment. Sedimentation equilibrium determines mass composition by analyzing the particle distribution once equilibrium between sedimentation and diffusion is reached. Analytical centrifugation is useful for determining properties like molecular weight, stoichiometry, assembly, and conformation.
The document summarizes research related to computational imaging being conducted by the Imaging Concepts group led by Prof. Andy Harvey at the University of Glasgow. Specific areas discussed include:
- Developing low-cost infrared camera array systems using computational techniques as an alternative to more complex optical setups.
- Applying techniques like synthetic aperture, light field imaging, temporal interpolation and pixel super-resolution to camera arrays.
- Demonstrating snapshot pixel super-resolution and integral imaging using a 5x5 camera array to produce higher resolution images.
- Developing a low-cost multispectral LWIR system using 6 FLIR LEPTON cameras and filters to enable applications like gas detection and classification
This document describes the validation of a high throughput electrochemical gas sensing screening system. Uniform thin film samples of YSZ and WO3 were developed and characterization using reflectometry and XRD confirmed their relative uniformity. Single and multielectrode cell tests were conducted on the samples at 600°C, showing their ability to detect different concentrations of NO gas. The system was able to conduct combinatorial screening of electrochemical gas sensors and validate the use of a planar sensor array design. Future work involves further optimizing the system.
ACEMD: High-throughput Molecular Dynamics with NVIDIA Kepler GPUsCan Ozdoruk
Acellera Founder Gianni De Fabritiis, and CTO Matt Harvey talk about the latest developments of high-throughput molecular dynamics both in terms of applications and methodological advances. Examples are in the context of ACEMD, a highly efficient, best-in-class graphical processing units (GPUs) centric code for running MD simulations, and its protocols. In particular, attendees will learn how the high arithmetic performance and intrinsic parallelism of the latest NVIDIA Kepler GPUs can offer a technological edge for molecular dynamics simulations. Try GPUs for free via: www.Nvidia.com/GPUTestDrive
The document summarizes a student project that developed a control strategy to test the capacity and efficiency aging of a domestic lithium-ion battery energy storage system (BESS). The project identified models of BESS operation and aging, an effective test methodology, designed and implemented a control system, and tested a BESS unit using the system. Key results showed an average capacity degradation of 0.16% per cycle and efficiency degradation of 0.07% per cycle over 15 cycles. The control strategy and testing approach can be applied to other BESS units for comparison.
This document summarizes research on applying principles from nature to architectural design. It explores concepts like lightness, emergence, and animal architecture found in nature. The research analyzed structural elements from living systems and how to design complex emergent structures from simple elements, similar to biological systems. The goal is to create designs that use less mass and energy through techniques like form-finding and understanding how an organism's properties depend on its growth and environment. The research aims to apply these natural principles to the design of the W.E.F.T. system through digital technologies and fabrication methods.
Bubble columns are widely used in the chemical and biochemical process industries. In order to develop design tools for engineering purposes, a large amount of research has been carried out in the area of CFD of gas-liquid flows. In this paper a transient Euler-Lagrange solver developed using the open source Caelus library is used to simulate the gas-liquid flow in a 3D square cross-sectioned bubble column. The turbulence is modelled using large eddy simulation (LES). The results of the simulations are compared to published PIV measurements. It is found that, good quantitative agreement with experimental data is obtained when drag, lift and virtual mass forces are used.
1) The document presents a study investigating the effect of microporosity on the longitudinal dispersion coefficient in porous media.
2) It develops an algorithm to simulate solute particle transport through porous media considering both advection and diffusion movements, as well as microporosity.
3) The results show that including microporosity increases the longitudinal dispersion coefficient, especially at higher Peclet numbers, with increases of up to 50% observed. This indicates microporosity has a significant impact on transport and has often been ignored in simulations.
An Autocorrelation Analysis Approach to Detecting Land Cover Change using Hyp...grssieee
The document presents an approach to detecting land cover change using temporal autocorrelation analysis of hyper-temporal satellite imagery. The methodology develops an autocorrelation-based change metric to distinguish real changes from natural phenological cycles. The optimal autocorrelation lag and detection threshold are determined using simulated change datasets. When applied to MODIS imagery of settlements in Gauteng, South Africa, the approach detected over 92% of real changes with an overall accuracy of 88%.
This study developed computational models to simulate the diffusion of vascular endothelial growth factor (VEGF) from hydrogel sources in a microfluidic device over 24 hours. A 2D stationary model, 1D time-dependent model, and 2D transient model were created in COMSOL to predict the VEGF gradient strength and diffusion distance over time. Sodium alginate and heparin-alginate hydrogels were also tested for sustained VEGF release by measuring protein concentration changes. The transient model predicted that the peak gradient strength would occur at 5 hours and that most VEGF would diffuse within 8 hours. Future work will use the heparin-alginate gels in cell migration assays to study how the VEGF gradient enhances
Master Thesis Presentation: Numerical Simulation of Modelled Blood Cells in a...Jesus Alvarez Sarro
This document summarizes a master's thesis presentation on numerically simulating modeled blood cells in viscous flow. The presentation includes sections on introduction, methodology, hydrodynamic effects, simulations with spheres and ellipsoids, and discussion. It describes grid generation studies, analysis of drag and lift forces on particles, velocity profiles, and the influence of particle concentration on focusing. Simulation results for spheres show they focus in two locations further downstream than experiments. Preliminary simulations with ellipsoids show only slight focusing, agreeing with experiments.
The document describes a study on the effect of holes on the tensile strength of composite materials created through hand layup. It outlines the goals to develop a hand layup procedure and test how holes influence composite strength. The methodology section explains the hand layup process and sample preparation/testing. Results show the material's properties are lower than expected and holes reduce strength. The characteristic length, over which stresses average around a hole, is calculated to be approximately 0.133 inches.
In this work, the synthetic Hydroxyapatite (HAP)
was studied using different preparation routes to
decrease the crystal size and was studied the
temperature effect on the nano-sized hydroxyapatite
crystallization. X-ray diffraction (XRD) analysis
indicated the all samples were composed by a
crystalline HAP phase and another amorphous part.
This paper applies inverse transform sampling to sample training points for surrogate models. Inverse transform sampling uniformly generates a sequence of real numbers ranging from 0 to 1 as the probabilities at sample points. The coordinates of the sample points are evaluated using the inverse functions of Cumulative Distribution Functions (CDF). The inputs to surrogate models are assumed to be independent random variables. The sample points obtained by inverse transform sampling can effectively represent the frequency of occurrence of the inputs. The distributions of inputs to the surrogate models are fitted to their observed data. These distributions are used for inverse transform sampling. The sample points have larger densities in the regions where the Probability Density Functions (PDF) are higher. This sampling approach ensures that the regions with higher densities of sample points are more prevalent in the observations of the random variables. Inverse transform sampling is applied to the development of surrogate models for window performance evaluation. The distributions of the following three climatic conditions are fitted: (i) the outside temperature, (ii) the wind speed, and (iii) the solar radiation. The sample climatic conditions obtained by the inverse transform sampling are used as training points to evaluate the heat transfer through a generic triple pane window. Using the simulation results at the sample points, surrogate models are developed to represent the heat transfer through the window as a function of the climatic conditions. It is observed that surrogate models developed using the inverse transform sampling can provide higher accuracy than that developed using the Sobol sequence directly for the window performance evaluation.
The document describes research into creating variable modulus hydrogels through a diffusion cycling process to fabricate multi-network gels with increasing mechanical strength and decreasing swelling ratio for use as tissue scaffolds. Experiments showed compressive and shear modulus increased over 3 diffusion cycles while gel fraction plateaued, indicating potential for tailoring hydrogel properties. Future work aims to further optimize mechanical properties and evaluate gels for regenerative medicine applications like 3D bioprinting of tissues.
Similar to Piske & Wassom Summer Presentation (20)
1. Studying the Mass Transport
Phenomena Associated with
Evaporation
Greg Wassom & Taylor Piske
Advised by Dr. Peter Kelly-Zion, Dr. Chris Pursell, and Dr. Hoa Nguyen
2. Details of Evaporation
Applications:
• Coating
• Spray cooling
• Printing
• Surface Patterning
• DNA stretching and depositing
Vapor Transport Mechanisms:
• Diffusion and Convection
Image take from: Lin, Zhiqun. Evaporative Self-Assembly of Ordered Complex Structures. World Scientific, 2012.
4. Buoyancy Induced Convection
Video taken from Sharma, Vidit. “VOF in Ansys Fluent 14”. https://www.youtube.com/watch?v=wys3qiBQzYY
• Bulk Transport
Phenomena
• Driven by a
Density
Gradient
• Gravity
5. Experimental Techniques
• Gravimetric Analysis
• Shadowgraph
• Pressure Chamber
• Schlieren Imaging
• IR Spectral Analysis
y = -0.1085x + 53.43
R² = 0.999
-10
0
10
20
30
40
50
60
0 100 200 300 400 500 600 700 800
Mass(mg)
Time (s)
Mass vs. Time
Measured Data
Fitted Slope (evaporation rate)
Linear (Fitted Slope (evaporation rate))
8. Using the Experimental Conc. Data with Gridfit
• MATLAB function Gridfit models the data with a surface
• Concentration gradients (
𝜕𝐶
𝜕𝑟
and
𝜕𝐶
𝜕𝑧
) are computed along a cylindrical
control volume
• Flux through the control volume is calculated
• Flux → Diffusion rate
0
5
10
15
20
-5 5 15 25 35
z-position(mm)
r-position (mm)
10. Methodology Check - Comparing Methanol
Diffusion Rates of Different Control Volumes
5.5E-08
6.0E-08
6.5E-08
7.0E-08
7.5E-08
8.0E-08
8.5E-08
9.0E-08
0.75 0.95 1.15 1.35 1.55 1.75 1.95 2.15 2.35 2.55 2.75
DiffusionRate(kg/s) Height of Control Volume (mm)
Diffusion Rates of Methanol Using Analytical Data
Methanol Theory
CV Radius = 8.5 mm
CV Radius = 8 mm
CV Radius = 7.5 mm
CV Radius = 7 mm
CV Radius = 6.5 mm
Theory
12. Comparing Diffusion Rates of Different
Control Volumes (Experimental Data)
0.0E+00
5.0E-08
1.0E-07
1.5E-07
2.0E-07
2.5E-07
0 0.5 1 1.5 2 2.5 3
DiffusionRate(kg/s)
Control Volume Height (mm)
Control Volume Radius = 7 mm
3MP
3MP Theory
Hexane
Hexane Theory
Methanol
Methanol Theory
0.0E+00
5.0E-08
1.0E-07
1.5E-07
2.0E-07
2.5E-07
3.0E-07
5.5 6 6.5 7 7.5 8 8.5 9
DiffusionRate(kg/s) Control Volume Radius (mm)
Control Volume Height = 1.5 mm
3MP
3MP Theory
Hexane
Hexane Theory
Methanol
Methanol Theory
13. Traditional Theory vs. Real Hexane Data
-25 -20 -15 -10 -5 0 5 10 15 20 25
Radial Position, r [mm]
Elevation,z[mm]
0
5
10
15
20
25
MeasuredComputed: Diffusion-Only
14. Summary
• Vapor concentration data measured for methanol, hexane, and 3-methylpentane
• Data modeled by Gridfit
• Gridfit model used to compute gradients, calculate diffusion rates
• Diffusion rates and theory compared
• Evidence of convection found
15. Acknowledgments
• Petroleum Research Fund
• Dr. Peter Kelly-Zion
• Dr. Chris Pursell
• Dr. Hoa Nguyen
• Chemistry Department, Trinity University
• Engineering Department, Trinity University
• Mathematics Department, Trinity University
Editor's Notes
Say: Evaporation is an important process involved in many applications. For instance, Surface patterning…(talk about surface patterns and why they are important)
Talk about how evaporation happens to different species in different ways, and has practical applications many people don’t think of.
Molecular Trqansport
Driven by concentration gradient
Bulk transport phenomena
Driven by density gradient
Bulk flow of vapors above a droplet moving away from their natural position due to a difference in density between the ambient gas and the evaporating droplet.
Because of this, there is room for more vapor to diffuse outward from the droplet.
Now imagine that just outside of the station, there is a tornado. Once people get outside, the gust takes them far away from the station.
Because of this, more room is present for people to escape out of the door in order to try to maintain equilibrium vapor pressure, so they do (escape), and the cycle continues until no one is left in the station.
This is an example of a density difference in the evaporating species, and the gases that it evaporates into, causing evaporation rates to be expedited.
This could happen the other way too. Imagine a lighter compound evaporating into a heavier one. This could be represented by a snowstorm which causes the exits in the train station to be blocked. Depending on how high the snow is outside, the evaporation rate changes up to the point where it can no longer escape.
Not worry about details involved in
Studying Evaporation (not rates)
In our lab, weve developed techniques to meaure and analyze evaporation rates.
Gravimetric Scale: Allows for comparison of evaporation rates in room temperature conditions across devices.
IR Spectrometer: Allows us to find concentrations of vapor clouds above droplets.
Pressure Chamber: Allows us to change ambient conditions around sessile droplets in order to see how they affect evaporation rates.
Shadowgraph: Imaging technique used in the pressure chamber which observes the droplet evaporate, and computes its rate of evaporation.
Schlieren Imaging: Allows observation of vapor clouds above droplets to see how distribution correlates with evaporation rates.
Use slides
Talk about how wavenumbers are chosen to integrate under.
Integration from 3200 to 2500 wavenumbers w/ baseline of the same
Try to change colors
Explain that this is infrared spectroscopy. This technique relates the absorbance of infrared light to the concentration of vapor. Absorbance is proportional to the concentration.
To measure vapor concentration, the IR beam of an FTIR is passed horizontally through the cloud at various locations above the drop. From these IR beam measurements, we will have a projection of the average concentration in the x-z plane. Each pass measures average absorption of vapor-air mixture in the path of the beam. (bottom image) this is the front profile of the vapor cloud and (point at the top left image) here is a top view of the vapor cloud. The measurements are done at multiple x-positions throughout the cloud. This is all for one elevation, this gives a 2 dimensional distribution. By repeating this process for multiple elevations, we can obtain a 3 dimensional distribution.