Determination of the optimal working fluid for the turbine recovering combustion engine exhaust gases heat

¹ Peter the Great St.Petersburg Polytechnic University, Polytechnicheskaya, 29, St. Petersburg, 195251, Russia
² Kazan State Power Engineering University, Kazan, Russian Federation

^* Corresponding author: matyury@mail.ru

Abstract

Microsteam turbine implementation for combustion engine exhaust gases heat recovery and subsequent acquisition of additional power is being investigated in many developed countries of the world. The results of such studies have already found application in some trucks. But this type of turbines is very weak in the Russian market. Turbine installation behind the combustion engine works under conditions of low volumetric flow of work fluid. This leads to a decrease in the height of the blade and vane wheels flow passage and an increase of the relative values of the gaps in the seals which are the reasons for the growth of the working fluid leakages. High degree of pressure reduction when selecting single-stage turbine leads to a supersonic velocity in the flow passage and an increase of the losses due to powerful shock waves. The efficiency of the turbine installation under these operating conditions is low and requires additional investigations. In this work, the working fluids which can give the greatest efficiency of the turbine installation were investigated. It was shown that not only thermodynamic but also hazardous and economic parameters must be taken into consideration. Working fluid with the high thermodynamic efficiency was compared with the one that profitable from economic point of view. The most appropriate substance was chosen and implemented in the microsteam turbine. The turbine stage which allows increasing economy and ecological compatibility of the combustion engine was developed and optimized by analytical methods.