Effects of Cone Angle and Inlet Blade Angle on Mixed Inflow Turbine Performances

Mohammed Hamel,Mohammed Kamel Hamidou,Mohammed Amine Chelabi

doi:10.3311/ppme.9890

Abstract

The development of the aerofoil-shaped turbomachine blades is of prime importance for achieving the appropriate deflection of a three dimensional flow through desired angles, to work at the same degree of incidence and thereby providing the required performances for the specific machine. The sensitivity of the rotor to incidence effects and tendency of the flow to separate from one or the other blade surface have given rise to considerations of the optimum incidence angle and cone angle for a mixed inflow turbine by a numerical investigation using the ANSYS-CFX code. In order to keep the rotor in the same casing some geometrical parameters have been hold constant and the Bezier polynomial is used to generate the new shape of the rotor blade when changing the cone angle magnitude.

Highlights

The mixed inflow turbines are suitable for many applications and particular attention is paid to systems where compact power sources are required, with higher boost pressure
7 Results and discussions The numerical simulations on the airfoil shaped blades for variable cone angles (20°, 30°, 40°, 45° and 50°) and different inlet blade angles (0°, 10°, 20° and 30°) have revealed some instructive results linked with the turbine total to static efficiency and the pressure distribution around the rotor blade which is related to the loading effect
In the case of parallel volute exit, it is noticed that in the range of inlet blade angle between 0° and 20°, all the concerned point except for the 50° cone angles, the curves are around the level of the maximum efficiency

Summary

Introduction

The mixed inflow turbines are suitable for many applications and particular attention is paid to systems where compact power sources are required, with higher boost pressure. Abidat [2] and Abidat et al [3] developed a new method of the blade profile generation by using the Bezier polynomials, showed that the Reducing of blade number for mixed-flow turbine with a constant blade angle from 12 to 10 leads to higher blade loading and results in about a 2% efficiency penalty. They were able to confirm a similar test result with Baines et al [1]. This increased flexibility can be used to great advantage in generating grids about arbitrary geometries

Flow simulations in a mixed inflow turbine

Results and discussions

The static pressure distribution around the blade at the mean radius

Conclusion