Computational Fluid Dynamics Simulation of the Effect of Guide-vane Angles on the Performance of the Exhaust Air Energy Recovery Turbine Generator

Abstract

An exhaust air energy recovery turbine generator is designed to recover part of the energy in the discharged air from an exhaust air system. The design is a combination of H-rotor vertical axis wind turbines (installed in cross-wind position), guide-vanes and a diffuser. Its working principle was tested on a scaled model of cooling tower and simulated in a computational fluid dynamic (CFD) package. From the guide-vanes study, optimum guide-vanes arrangement is 100̊, 70̊ and 90̊. The system with optimized guide-vanes arrangement produced the highest torque coefficient compared to the other configurations. The average torque coefficient of the system was increased by 24.3% with the introduction of diffuser and guide-vanes at optimized angles, i.e. from 0.029 to 0.036. From the graph of the torque coefficient versus azimuth angle, the overall positive torque zone was increased with the introduction of the guide-vanes with optimum configuration. The exhaust air energy recovery turbine generator can be another green technology that recovers waste energy from the discharged wind of an exhaust air system for urban areas.