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热力学代写 Thermodynamics代写

2021-10-25 14:00 星期一 所属： 作业代写 浏览：36

Design Problem, 100 pts

The design project for ME 523 consists calculating and plotting ideal open Brayton cycle performance, calculating combustion characteristics of a typical natural gas mixture in air, and the simulation of the General Electric (GE) HA9 utility gas turbine fueled with the same natural gas. Only the engine’s ambient air design operating characteristics at ISO standard conditions is requested which are 59oF and 14.7 psia. Assume that the effects of air relative humidity is negligible. Thus, off-design considerations will not be investigated (i.e. variable ambient temperature and pressure, and engine throttle setting are not considered for this project). This project is composed of three parts, each “building” on the previous part. Consequently, proceed through the project in the order of the parts.

Software is, of course, expected to be used in making your computations for all three parts. EES (Engineering Equation Solver) is to be used when developing your simulations. EES is available on the MNE network (intranet) and so access to it is straight forward. EES has built-in routines for thermodynamic property evaluation.

submission  热力学代写

The KSU Honor Pledge relying on each student’s integrity continues through this assignment.

Special recognition software will be applied to reports and EES codes to uncover similarities among student submissions. Discoveries made will be reported as a violation of the KSU Honor Pledge.

Part 1. (30 pts)  热力学代写

The objective of Part (1.) is to predict the performance of an open ideal Brayton cycle using air as the working fluid. The cycle’s net output power as a function of compressor pressure ratio and turbine inlet temperature is to be computed. The ranges of compressor pressure ratio and turbine inlet temperature are:

Compressor pressure ratio: 10 –to– 30 (increment = 2)

Turbine inlet temperature: 1600°F –to– 3000°F (increment = 200°F)

Make a plot of net output power (Btu/lbm) (y-axis) versus compressor pressure ratio (x-axis) with each line in the plot for a constant turbine inlet temperature. Fully discuss what these results mean. Submit the EES program you used to generate the results and the EES generated plot.

Part 3.) (40 pts)  热力学代写

Your objective is to simulate the operation of the GE HA9 gas turbine engine using the important characteristics provided by GE at ISO conditions:

Net Power Output = 397 MW
Exhaust mass flow = 1822 lbm/sec
Exhaust gas temperature = 1146°F
Maximum turbine inlet temperature = 2580°F

plus those provided in the GE literature. The above four characteristics shall be considered constants with the exception of the turbine inlet temperature which cannot be exceeded.

However, engine characteristics not considered constants are: compressor isentropic efficiency, entering air temperature to the turbine, combustor thermal efficiency, and turbine isentropic efficiency. Your results for this part are the estimates of the turbine inlet temperature and the three GT component efficiencies such that all the engine’s four constant characteristics above are predicted to within 2%. Use your tables and plots demonstrating the “goodness” of your predictions.

The EES calculations developed in Parts (1.) and (2.) must be incorporated as appropriate into the your EES code for this part. The required tolerance of your predicted values to the above four characteristics is two percent or less. Use the lower heating value of the fuel’s composition and realize that the fuel flow adds mass flow to engine’s inlet air. It is very important that you thoroughly discuss what you did, or did not, in attempting to achieve the 2% matching goal for the four characteristics above.

Useful Background Information   热力学代写

1.) Consider a gas turbine engine operating with the following known information:10-30-2020 version

Compressor pressure ratio, rc =30.0
Combustor efficiency, ηcomb = 0.95
Combustor inlet temperature, T2 = 1060°R
Combustor exit temperature, T3 = 2380°R
Fuel Lower Heating Value, LHV = 18,670 Btu/lbm fuel (JP4 fuel)
cp (average) = 0.25 Btu / lbm-°R
FAstoich = 0.067

To determine the actual FA ratio to obtain T3, utilize an energy balance on the combustor where the energy added by the incoming fuel’s combustion is equal to the enthalpy increase of the air passing through. So,

However, note that at this low FA ratio, the fuel-air mixture will not ignite nor sustain combustion. The lower limit of the FA ratio supporting combustion is about 0.03.

2.) To achieve sustainable combustion, less than half of the compressor’s exit flow must pass through the combustor’s combustion zone which is immediately downstream from the fuel nozzle. The remaining air not passing through the combustion zone cools the combustor metal liner and dilutes the combustion products to decrease the temperature downstream from the combustion zone. At the exit of the combustor the products temperature is equal to the turbine inlet temperature. The figures below illustrate the cooling and dilution processes in the combustor. Realize that the percent flows are only indicative of reasonable magnitudes.

Figure 1. Combustion chamber for a gas turbine engine. (Hill and Peterson, Mechanics and  Thermodynamics of Propulsion, 2nd Ed., Addison-Wesley, Reading, MA (1992)

Figure 2. Illustrative air flow distribution in a gas turbine combustor. (Hill and Peterson, Mechanics and Thermodynamics of Propulsion, 2nd Ed., Addison-Wesley, Reading, MA (1992)