SINGLE PASSAGE CFD ANALYSIS FOR NON-RADIAL FIBRE ELEMENT OF LOW PRESSURE TURBINE

Abstract

Low Pressure Turbine (LPT) is a mixed-flow low pressure turbine meant for extracting energy from the exhaust of internal combustion engine. It converts the expanded exhaust energy into mechanical energy to drive an electric generator. The current available design of the LPT is only able to recover the exhaust energy efficiently with a pressure ratio range of 1.04 to 1.30. However, the performance efficiency deteriorates significantly when the pressure ratio exceeds 1.25. In the previous studies, flow field analysis has shown that the entropy is largely generated at the exit due to bigger vorticity. This vorticity can be minimized by optimizing the exit flow direction. This can be done by adjusting the exit camberline which reduces the deflection angle of the flow. This will effect exit flow of the fluid; subsequently reduces the exit loss as stipulated in the 1-Dimensional analysis of the turbine. Results have shown that the overall efficiency of the turbine has been improved as much as 7% at pressure ratios of 1.20. Its swallowing capacity is not largely affected at this point and its velocity ratio has shifted slightly from its design point of 0.70 to 0.65.