Development of a chassis mounted multi stage axial flow turbine for wind energy harvesting on a cruising transport vehicle - A CFD based approach

Abstract

Fossil fuels have been a means of energy source since a long time, and have tended to the needs of the large global population. These conventional sources are bound to deplete in the near future and hence there is a need for producing energy from renewable energy sources like solar, wind, geothermal, tidal etc. Technologies involving renewable energy are a growing subject of concern. Further, the problem is also one of excessive pollution caused by conventional sources of energy and their impact on the environment. In particular, one of the main sources of pollution is harmful gases emitting out of automobiles. Wind energy is one among the renewable energy sources which is implemented in large scale energy production to supplement growing domestic energy needs. Significant amount of research has been done in this field to harness energy to power household and other amenities using wind farms. The aim of this project is to come up with a low cost solution for wind energy harvesting on moving vehicles. The purpose of this study is to consider the use of wind energy along with conventional energy sources to power automobiles. This would help reduce the use of fossil fuels in automobiles and hence reduce the resulting environmental pollution. Also since the turbine adds to the weight of the vehicle the aim also is to minimize the weight of the turbine. Extensive structural analysis is done for this purpose to choose a material which would be both light weight and also be able to withstand the stresses developed. In the current paper the drag force produced in automobiles is harvested by using a convergent divergent nozzle mounted below the chassis of the car. Initially drag analysis is done in order to determine the increase in drag force produced after mounting of the nozzle. It is found from existing literature that the drag increases by 3.4% after the mounting of the nozzle making it possible the mounting of a nozzle beneath the car. Additionally exhaust gases is also allowed to pass through the same duct to increase the mass flow to the turbine and thus generate more energy. This is made to strike the blades of a 2 stage axial flow turbine whose rotation generates energy. The power output from the turbine is the parameter of interest. This energy can also be stored in batteries and be used to run auxiliary equipment of the automobile including the air conditioner. The exhaust gases will be passed through a catalytic converter before striking the blades of the turbine in order to prevent corrosion of the blades. Computational Fluid Dynamics (CFD) is used to validate the concept and also come up with a design that maximizes energy generation by such turbines. Numerical results obtained by simulation are validated by theoretical calculation based on turbines inlet and outlet velocity triangles. The future scope of the project would include the use of multiple nozzles in order to study its performance. � Copyright 2016 by ASME.