The document summarizes the key components and functioning of a gas turbine combustion chamber. It describes the combustion chamber, diffuser, liner, snout, dome, and swirler. The combustion chamber must stabilize flames in a continuous high-velocity air flow. It utilizes techniques like bluff bodies or swirl to generate recirculation zones for ignition and flame anchoring. The liner must withstand high temperatures and is cooled using film or transpiration cooling techniques.
vapor absorption system,three fluid vapor absorption system,water and ammonia vapor absorption system water and lithium bromide vapor absorption system
vapor absorption system,three fluid vapor absorption system,water and ammonia vapor absorption system water and lithium bromide vapor absorption system
Compressors complete description and a well arranged slides for the topic. That's too the point and relevant slide share you are looking for! Hope you will find it easy to understand
Thank you!
Thermal Power Plant Boiler Efficiency ImprovementAnkur Gaikwad
Boiler is one of the central equipment used in power generation & chemical process industries. Consequently, improving boiler efficiency is instrumental in bringing down costs substantially with a few simple measures. Some of these measures are discussed in this presentation
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
Compressors complete description and a well arranged slides for the topic. That's too the point and relevant slide share you are looking for! Hope you will find it easy to understand
Thank you!
Thermal Power Plant Boiler Efficiency ImprovementAnkur Gaikwad
Boiler is one of the central equipment used in power generation & chemical process industries. Consequently, improving boiler efficiency is instrumental in bringing down costs substantially with a few simple measures. Some of these measures are discussed in this presentation
STEAM JET COOLING SYSTEM
Steam jet cooling system is a cooling technique which involves usage of steam and water for cooling purposes. In steam jet refrigeration systems, water can be used as the refrigerant. Like air, it is perfectly safe. These systems were applied successfully to refrigeration.
•Temperatures attained using water as a refrigerant are in the range which may satisfy air conditioning, cooling, or chilling requirements.
•Mostly low-grade energy and relatively small amounts of shaft work.
•This system are the utilization of mostly low-grade energy and relatively small amounts of shaft work.
•Not used when temperatures below 5°C are required.
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Enhancement of Specific Power Output of a Gas Turbine Using Filtered Chilled AirIOSR Journals
Conventionally the specific power output of the gas turbine can be increased using reheating and
intercooling. The thermal efficiency can be improved by adding a regenerating at lower pressure ratios. In the
present work the emphasis is given to enhance the specific power output by other means like reduction in the air
temperature at the inlet duct. The power output of the gas turbine has been estimated by allowing air at reduced
temperatures, step wise. The experiment is conducted till STP conditions are attained. The chiller coils are used
for inlet air cooling. The variation of power output with respect to temperature is also studied.
The CFD Analysis of Turbulence Characteristics in Combustion Chamber with Non...IOSR Journals
Abstract : Co-Axial jets have applications in areas where the mixing of two fluid jets are necessary, the two
fluid jets can be effectively mixed by producing the turbulence flow. Turbulence is a chaotic behavior of the fluid
particles that comes in to picture when the inertia force of the flow dominates the viscous force and it is
characterized by the Reynolds Number. Co-axial jets are effective in producing the turbulence. In the present
study the free compressible turbulent coaxial jet problem will be computed using CFD, and compare with
different non circular coaxial jets based on constant hydraulic diameter and mass flow rate. Turbulence
characteristics of combustion chamber with circular coaxial and non circular coaxial jets are determined and
compared.
Keywords: Coaxial Jet, Turbulence Modeling, Fuel injector, Combustion chamber.
Review of Gas Turbine Combustion Chamber Designs to Reduce EmissionsIJAEMSJORNAL
Ensuring the environmental safety of aircraft engines is an important task for developers. This problem is becoming more urgent due to an increase in engine power, since an increase in power is achieved primarily by increasing the temperature in the combustion chamber, leading to an increase in NOx emissions. In this study, the problem of emission in the aviation industry and ways to solve it were considered. Separately, the method of reducing emissions by changing the design of combustion chambers was considered in more detail.
Thermal Engineering is a specialised sub-discipline of Mechanical Engineering that deals exclusively with heat energy and its transfer between not only different mediums, but also into other usable forms of energy. A Thermal Engineer will be armed with the expertise to design systems and process to convert generated energy from various thermal sources into chemical, mechanical or electrical energy depending on the task at hand. Obviously, all Thermal Engineers are experts in all aspects of heat transfer.
Many process plants (basically somewhere where some raw material or resource is converted into something useful, e.g. power plants, oil refineries, plastic manufacturing plants, etc.) contain countless components and systems which have to be designed in terms of their heat transfer; it is particularly important to ensure that not too much heat is retained so the component or process is not disrupted. Conversely, some processes or systems are designed to use heat to their advantage and a Thermal Engineer must make sure enough heat is generated and used wisely (i.e. sustainably).
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)
Combustion chamber of Gas turbine power plant cycle
1. BEANT COLLEGE OF ENGINEERING AND TECHNOLOGY
GURDASPUR
Seminar report (TH-590)
TOPIC- Study of the Combustion chamber of the Gas turbine Power plant
Submitted To: Submitted By:
Dr. Jagdev Singh Davinder Singh
Associate Professor Thermal Engg. (Sem-3)
Mech. Department. College R.No. 204/13
2. Combustion Chamber of Gas turbine Power Plant Cycle
INTORUCTION
The simplest form of gas turbine requires three components: the gas turbine itself, a compressor, and a combustor in which fuel is mixed with air and burned. These three basic elements are depicted schematically in Figure
Open cycle gas turbine.
COMBUSTION CHAMBERS
The gas turbine is a continuous flow system; therefore, the combustion in the gas turbine differs from the combustion in diesel engines. High rate of mass flow results in high velocities at various points throughout the cycle (300 m/sec). One of the vital problems associated with the design of gas turbine combustion system is to secure a steady and stable flame inside the combustion chamber. The gas
3. turbine combustion system has to function under certain different operating conditions which are not usually met with the combustion systems of diesel engines. A few of them are listed below:
Combustion in the gas turbine takes place in a continuous flow system and, therefore, the advantage of high pressure and restricted volume available in diesel engine is lost. The chemical reaction takes place relatively slowly thus requiring large residence time in the combustion chamber in order to achieve complete combustion.
The gas turbine requires about 100:1 air-fuel ratio by weight for the reasons mentioned earlier. But the air-fuel ratio required for the combustion in diesel engine is approximately 15:1. Therefore, it is impossible to ignite and maintain a continuous combustion with such weak mixture. It is necessary to provide rich mixture fm ignition and continuous combustion, and therefore, it is necessary to allow required air in the combustion zone and the remaining air must be added after complete combustion to reduce the gas temperature before passing into the turbine.
A pilot or recalculated zone should be created in the main flow to establish a stable flame that helps to ignite the combustible mixture continuously.
A stable continuous flame can be maintained inside the combustion chamber when the stream velocity and fuel burning velocity are equal. Unfortunately most of the fuels have low burning velocities of the order of a few meters per second; therefore, flame stabilization is not possible unless some technique is employed to anchor the flame in the combustion chamber.
4. Combustion Chamber with Downstream Injection and Swirl Holder
The common methods of flame stabilization used in practice are bluff body method and swirl flow method. Two types of combustion chambers using bluff body and swirl for flame stabilization. The major difference between two is the use of different methods to create pilot zone for flame stabilization. Nearly 15 to 20% of the total air is passed around the jet of fuel providing rich mixture in the
primary zone. This mixture burns continuously in the primary (pilot) zone and produces high temperature gases. About 30% of the total air is supplied in the secondary zone through the annuals around the flame tube to complete the combustion. The secondary air must be admitted at right points in the combustion chamber otherwise the cold injected air may chill the flame locally thereby reducing the rate of reaction. The secondary air helps to complete the
5. combustion as well as helps to cool the flame tube. The remaining 50% air is mixed with burnt gases in the “tertiary zone” to cool the gases down to the
Temperature suited to the turbine blade materials. By inserting a bluff body in mainstream, a low-pressure zone is created downstream side that causes the reversal of flow along the axis of the combustion chamber to stabilize the flame.
In case of swirl stabilization, the primary air is passed through the swirled, which produces a vortex motion creating a low-pressure zone along the axis of the chamber to cause the reversal of flow. Sufficient turbulence must be created in all three zones of combustion and uniform mixing of hot and cold bases to give uniform temperature gas stream at the outlet of the combustion chamber.
Four steps of Combustion process
Formulation of reactive mixture
Ignition
Flame propagation
Cooling of combustion product with air
Formulation of reactive mixture
Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the products leading to the insight that the relations among quantities of reactants and products typically form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of product can be empirically determined, then the amount of the other reactants can also be calculated.
As seen in the image to the right, where the balanced equation is:
6. CH4 + 2 O2 → CO2 + 2 H2O
Here, one molecule of methane reacts with two molecules of oxygen gas to yield one molecule of carbon dioxide and two molecules water. Stoichiometry measures these quantitative relationships, and is used to determine the amount of products/reactants that are produced/needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry. In the example above, reaction stoichiometry measures the relationship between the methane and oxygen as they react to form carbon dioxide and water.
Because of the well-known relationship of moles to atomic weights, the ratios that are arrived at by stoichiometry can be used to determine quantities by weight in a reaction described by a balanced equation. This is called composition stoichiometry.
Components
7. Case
The case is the outer shell of the combustor, and is a fairly simple structure. The casing generally requires little maintenance. The case is protected from thermal loads by the air flowing in it, so thermal performance is of limited concern. However, the casing serves as a pressure vessel that must withstand the difference between the high pressures inside the combustor and the lower pressure outside. That mechanical (rather than thermal) load is a driving design factor in the case.
Diffuser
The purpose of the diffuser is to slow the high speed, highly compressed, air from the compressor to a velocity optimal for the combustor. Reducing the velocity results in an unavoidable loss in total pressure, so one of the design challenges is to limit the loss of pressure as much as possible. Furthermore, the diffuser must be designed to limit the flow distortion as much as possible by avoiding flow effects like boundary layer separation. Like most other gas turbine engine components, the diffuser is designed to be as short and light as possible.
Liner
The liner contains the combustion process and introduces the various airflows (intermediate, dilution, and cooling, see Air flow paths below) into the combustion zone. The liner must be designed and built to withstand extended high temperature cycles. For that reason liners tend to be made from superalloys like Hastelloy X. Furthermore, even though high performance alloys are used, the
8. liners must be cooled with air flow. Some combustors also make use of thermal barrier coatings. However, air cooling is still required. In general, there are two main types of liner cooling; film cooling and transpiration cooling. Film cooling works by injecting (by one of several methods) cool air from outside of the liner to just inside of the liner. This creates a thin film of cool air that protects the liner, reducing the temperature at the liner from around 1800 kelvins (K) to around 830 K, for example. The other type of liner cooling, transpiration cooling, is a more modern approach that uses a porous material for the liner. The porous liner allows a small amount of cooling air to pass through it, providing cooling benefits similar to film cooling. The two primary differences are in the resulting temperature profile of the liner and the amount of cooling air required. Transpiration cooling results in a much more even temperature profile, as the cooling air is uniformly introduced through pores. Film cooling air is generally introduced through slats or louvers, resulting in an uneven profile where it is cooler at the slat and warmer between the slats. More importantly, transpiration cooling uses much less cooling air (on the order of 10% of total airflow, rather than 20-50% for film cooling). Using less air for cooling allows more to be used for combustion, which is more and more important for high performance, high thrust engines.
Snout
The snout is an extension of the dome that acts as an air splitter, separating the primary air from the secondary air flows (intermediate, dilution, and cooling air; see Air flow paths section below).
9. Dome / swirler
The dome and swirler are the part of the combustor that the primary air (see Air flow paths below) flows through as it enters the combustion zone. Their role is to generate turbulence in the flow to rapidly mix the air with fuel.Early combustors tended to use bluff body domes (rather than swirlers), which used a simple plate to create wake turbulence to mix the fuel and air. Most modern designs, however, are swirl stabilized (use swirlers). The swirler establishes a local low pressure zone that forces some of the combustion products to recirculate, creating the high turbulence. However, the higher the turbulence, the higher the pressure loss will be for the combustor, so the dome and swirler must be carefully designed so as not to generate more turbulence than is needed to sufficiently mix the fuel and air.
Fuel injector
Fuel injectors of a cannular combustor on a Pratt & Whitney JT9D turbofan
The fuel injector is responsible for introducing fuel to the combustion zone and, along with the swirler (above), is responsible for mixing the fuel and air. There are four primary types of fuel injectors; pressure-atomizing, air blast, vaporizing, and premix/prevaporizing injectors. Pressure atomizing fuel injectors rely on high fuel pressures (as much as 500 pounds per square inch (psi) to atomize the fuel. This
10. type of fuel injector has the advantage of being very simple, but it has several disadvantages. The fuel system must be robust enough to withstand such high pressures, and the fuel tends to be heterogeneously atomized, resulting in incomplete or uneven combustion which has more pollutants and smoke.
The second type of fuel injector is the air blast injector. This injector "blasts" a sheet of fuel with a stream of air, atomizing the fuel into homogeneous droplets. This type of fuel injector led to the first smokeless combustors. The air used is just some amount of the primary air (see Air flow paths below) that is diverted through the injector, rather than the swirler. This type of injector also requires lower fuel pressures than the pressure atomizing type.
The vaporizing fuel injector, the third type, is similar to the air blast injector in that primary air is mixed with the fuel as it is injected into the combustion zone. However, the fuel-air mixture travels through a tube within the combustion zone. Heat from the combustion zone is transferred to the fuel-air mixture, vaporizing some of the fuel (mixing it better) before it is combusted. This method allows the fuel to be combusted with less thermal radiation, which helps protect the liner. However, the vaporizer tube may have serious durability problems with low fuel flow within it (the fuel inside of the tube protects the tube from the combustion heat).
The premixing injectors work by mixing or vaporizing the fuel before it reaches the combustion zone. This method allows the fuel to be very uniformly mixed with the air, reducing emissions from the engine. One disadvantage of this method is that fuel may auto-ignite or otherwise combust before the fuel-air
11. mixture reaches the combustion zone. If this happens the combustor can be seriously damaged.
Igniter
Most igniters in gas turbine applications are electrical spark igniters, similar to automotive spark plugs . The igniter needs to be in the combustion zone where the fuel and air are already mixed, but it needs to be far enough upstream so that it is not damaged by the combustion itself. Once the combustion is initially started by the igniter, it is self-sustaining and the igniter is no longer used. In can-annular and annular combustors the flame can propagate from one combustion zone to another, so igniters are not needed at each one. In some systems ignition-assist techniques are used. One such method is oxygen injection, where oxygen is fed to the ignition area, helping the fuel easily combust. This is particularly useful in some aircraft applications where the engine may have to restart at high altitude.
Air flow paths
12. Primary air
This is the main combustion air. It is highly compressed air from the high pressure compressor (often decelerated via the diffuser) that is fed through the main channels in the dome of the combustor and the first set of liner holes. This air is mixed with fuel, and then combusted.
Intermediate air
Intermediate air is the air injected into the combustion zone through the second set of liner holes (primary air goes through the first set). This air completes the reaction processes, cooling the air down and diluting the high concentrations of carbon monoxide (CO) and hydrogen (H2).
Dilution air
Dilution air is airflow injected through holes in the liner at the end of the combustion chamber to help cool the air to before it reaches the turbine stages. The air is carefully used to produce the uniform temperature profile desired in the combustor. However, as turbine blade technology improves, allowing them to withstand higher temperatures, dilution air is used less, allowing the use of more combustion air.
Cooling air
Cooling air is airflow that is injected through small holes in the liner to generate a layer (film) of cool air to protect the liner from the combustion temperatures. The implementation of cooling air has to be carefully designed so it does not directly interact with the combustion air and process. In some cases, as much as 50% of the inlet air is used as cooling air. There are several different methods of injecting this cooling air, and the method can influence the temperature profile.
13. Types of combustion Chamber
Can Type of Combustion Chamber
Arrangement of can-type combustors for a gas turbine engine, looking axis on, through the exhaust. The blue indicates cooling flow path, the orange indicates the combustion product flow path.
Can combustors are self-contained cylindrical combustion chambers. Each "can" has its own fuel injector, igniter, liner, and casing. The primary air from the compressor is guided into each individual can, where it is decelerated, mixed with fuel, and then ignited. The secondary air also comes from the compressor, where it is fed outside of the liner (inside of which is where the combustion is taking place). The secondary air is then fed, usually through slits in the liner, into the combustion zone to cool the liner via thin film cooling.
14. In most applications, multiple cans are arranged around the central axis of the engine, and their shared exhaust is fed to the turbine(s). Can type combustors were most widely used in early gas turbine engines; owing to their ease of design and testing (one can test a single can, rather than have to test the whole system). Can type combustors are easy to maintain, as only a single can needs to be removed, rather than the whole combustion section. Most modern gas turbine engines (particularly for aircraft applications) do not use can combustors, as they often weigh more than alternatives. Additionally, the pressure drop across the can is generally higher than other combustors. Most modern engines that use can combustors are turbo shafts featuring centrifugal compressors.
Cannular
Cannular combustor for a gas turbine engine, viewing axis on, through the exhaust.
The next type of combustor is the cannular combustor; the term is a portmanteau of "can annular". Like the can type combustor, can annular combustors have discrete combustion zones contained in separate liners with their own fuel injectors. Unlike the can combustor, all the combustion zones share a common ring (annulus) casing. Each combustion zone no longer has to serve as a pressure vessel. The combustion zones can also "communicate" with each other via liner holes or connecting tubes that allow some air to flow circumferentially. The exit flow from the cannular combustor generally has a more uniform temperature profile, which is better for the turbine section. It also eliminates the need for each chamber to have its own igniter. Once the fire is lit in one or two cans, it can
15. easily spread to and ignite the others. This type of combustor is also lighter than the can type, and has a lower pressure drop (on the order of 6%). However, a cannular combustor can be more difficult to maintain than a can combustor. An example of a gas turbine engine utilizing a cannular combustor is the General Electric J79 The Pratt & Whitney JT8D and the Rolls-Royce Tay turbofans use this type of combustor as well.
Annular
Annular combustor for a gas turbine engine, viewed axis on looking through the exhaust. The small orange circles are the fuel injection nozzles.
The final and most commonly used type of combustor is the fully annular combustor. Annular combustors do away with the separate combustion zones and simply have a continuous liner and casing in a ring (the annulus). There are many advantages to annular combustors, including more uniform combustion,
16. shorter size (therefore lighter), and less surface area. Additionally, annular combustors tend to have very uniform exit temperatures. They also have the lowest pressure drop of the three designs (on the order of 5%). The annular design is also simpler, although testing generally requires a full size test rig. An engine that uses an annular combustor is the CFM International CFM56. Most modern engines use annular combustors; likewise, most combustor research and development focuses on improving this type.
Double annular combustor
One variation on the standard annular combustor is the double annular combustor (DAC). Like an annular combustor, the DAC is a continuous ring without separate combustion zones around the radius. The difference is that the combustor has two combustion zones around the ring; a pilot zone and a main zone. The pilot zone acts like that of a single annular combustor, and is the only zone operating at low power levels. At high power levels, the main zone is used as well, increasing air and mass flow through the combustor. GE's implementation of this type of combustor focuses on reducing NOx and CO2 emissions. A good diagram of a DAC is available from Purdue. Extending the same principles as the double annular combustor, triple annular and "multiple annular" combustors have been proposed and even patented.
Fundamentals
The objective of the combustor in a gas turbine is to add energy to the system to power the turbines, and produce a high velocity gas to exhaust through the nozzle in aircraft applications. As with any engineering challenge, accomplishing this requires balancing many design considerations, such as the following:
Completely combust the fuel. Otherwise, the engine is just wasting the unburnt fuel.
Low pressure loss across the combustor. The turbine which the combustor feeds needs high pressure flow to operate efficiently.
17. The flame (combustion) must be held (contained) inside of the combustor. If combustion happens further back in the engine, the turbine stages can easily be damaged. Additionally, as turbine blades continue to grow more advanced and are able to withstand higher temperatures, the combustors are being designed to burn at higher temperatures and the parts of the combustor need to be designed to withstand those higher temperatures.
Uniform exit temperature profile. If there are hot spots in the exit flow, the turbine may be subjected to thermal stress or other types of damage. Similarly, the temperature profile within the combustor should avoid hot spots, as those can damage or destroy a combustor from the inside.
Small physical size and weight. Space and weight is at a premium in aircraft applications, so a well-designed combustor strives to be compact. Non- aircraft applications, like power generating gas turbines, are not as constrained by this factor.
Wide range of operation. Most combustors must be able to operate with a variety of inlet pressures, temperatures, and mass flows. These factors change with both engine settings and environmental conditions (I.e., full throttle at low altitude can be very different from idle throttle at high altitude).
Environmental emissions. There are strict regulations on aircraft emissions of pollutants like carbon dioxide and nitrogen oxides, so combustors need to be designed to minimize those emissions.
18. Question- What is the ignition temperature of the kerosene?
Answer- The flash point of kerosene is between 37 and 65 °C (100 and 150 °F), and its auto ignition temperature is 220 °C (428 °F).
Question- Why we increase the pressure of the working fluid in gas turbine power plant?
Answer- The pressure is increased by the compressor of the working fluid in Gas turbine power plant. This increase in pressure is converted into kinetic energy of the working fluid with the help of the convergent nozzle.
Convergent nozzle
If the inlet pressure at the inlet of nozzle is equal to the exit of the nozzle then there is no increase in the velocity of the working fluid. So we cannot obtain the work on the turbine.
19. Question- Which parameters are effects on the flame propagation in the Combustion chamber?
Answer- The main parameters which are the effect the flame propagation Inflammability of the fuel being used, pressure, temperature. The theory of flame propagation in slow inflammation is proposed which considers that the highly energized atoms or radicals formed in the flame front play a more important role than heat conductivity in bringing the unburned gas to the reacting state. A small number of atoms or radicals diffuse over into the unburned phase, there initiating the chemical reaction. This and other considerations allow one to propose that the sum of thermal and chemical energy per unit mass of gas in all layers from the burned phase to the unburned phase is constant. The fundamental equation for the velocity V of the flame is derived simply from the fact that the number of molecules of combustible gas entering the reaction zone (flame front) in unit time equals the number reacting in the zone in the same time.
Question- Define mass flow rate?
Answer- In physics and engineering, mass flow rate is the mass of a substance which passes per unit of time. Its unit is kilogram per second in SI units. The common symbol is is used.
Mass flow rate is defined by the limit:
i.e. the flow of mass m through a surface per unit time t.
20. Alternative equations
Mass flow rate can also be calculated by:
where:
or Q = Volume flow rate,
ρ = mass density of the fluid,
v = Flow velocity of the mass elements,
A = cross-sectional vector area/surface,
jm = mass flux.