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Regenerative Brayton Cycle Analysis

Decent Essays

MAE 336
(Power Plant Design)

Design Project 1:
Regenerative Brayton Cycle

Date Submitted: 4/02/2012

Garrett Kinsel
ID#: 003800821

Mon/Wed 9:00am-11:15am

Instructor: Dr. Torabzadeh, Ph.D.

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ABSTRACT

The purpose of this design project was to investigate the effect of various design and operating parameters on the thermal efficiency, net work output per unit mass, and back work ratio of a regenerative Brayton cycle. Specifically, these parameters include the pressure ratio, TminTmax ratio, regenerator effectiveness, and compressor and turbine efficiencies, assuming the working fluid to be air at 100kPa and 300K at the compressor inlet. Model calculations are presented …show more content…

Due to their low overall thermal efficiencies, gas turbines initially had limited uses. As time has passed, many renovations have been implemented to the gas turbine cycle to make it more efficient. Some modifications include: increasing the turbine inlet temperatures, increasing the efficiencies of turbo machinery components, and adding modifications to the basic cycle. In contrast to the ideal cycle, the actual cycle undergoes unavoidable pressure drops during the heat addition and heat rejection processes. In addition, the actual work input to the compressor is always more than the output and the actual work output of the turbine is less than the work input due to irreversibility. These relationships are displayed in the figures below:

Four other common modifications to the simple ideal and actual Brayton cycles include: 1) Regeneration 2) Reheat 3) Intercooling 4) Regeneration with Reheat and Intercooling
The only methods amongst these choices that improve the overall thermal efficiency of the ideal Brayton cycle are those that utilize regeneration. However, each of these four improvements also increase the initial cost of building the equipment as well as the maintenance cost for the cycle. Thus, deciding which power cycle to build depends on economics as much as it depends on engineering.
A

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