جستجوی مقالات مرتبط با کلیدواژه "loss coefficients" در نشریات گروه "مکانیک"

Exergy analysis of a system is a method for recognizing the value and type of system availability against surrounding environment. It also helps to find how macroscopic properties of the system change during a process. This analysis is based on first and second laws of thermodynamics. By exergy analysis proportion of each process in the internal availability transmission and the places of useful energy losses in the system can be determined. In this research exergy analysis of radial flow compressor in the various working conditions is considered. So، the approach for compressor modeling by assumption of one dimensional ideal gas flow is considered. In this method the secondary flow effects and the other real flow losses are added to the model by the appropriate loss coefficients that almost are attained by experimental results. In the one dimensional analysis، compressor components are studied separately and with regard to inlet stagnation properties، passing flow duct geometry and present losses. Thus، the performance characteristics of compressor are estimated with average relative errors of 7 and 10 percent for pressure ratio and efficiency respectively. From the presented results it can be concluded that maximum efficiency location is coincide with location of minimum incidence loss at inducer and this point is transferred to further flow rates by increasing impeller speed.

In this paper، thermodynamic design of an axial flow power turbine for converting an existing turbojet to a turbo-shaft engine is presented. The exhaust nozzle of the turbojet is replaced by an axial flow power turbine. The turbine model is developed، based on Ainley-Mathieson model. The results of Ainley-Mathieson model were verified، using a 3D simulation and existing experimental data. The turbine performance was investigated for several blade angles of attack. Results show that the turbine stage has a minimum loss and a maximum efficiency، when angles of attack are -3 degrees for stator and -8 degrees for rotor blades.