A Three-Dimensional Conjugate Heat Transfer Model of a Turbocharger Turbine Housing

Abstract

The turbine housing is subjected to thermal load which is essential to be taken into account in the design process. In this paper, a three-dimensional conjugate heat transfer simulation of a wastegated turbine housing has been performed. The model has been validated with data from thermocouple measurements and thermography pictures. Moreover, the effect of ventilation speed on temperature distribution of turbine housing is investigated. As the air velocity increases from 8 to 20 m/s, the turbine housing temperature decreases about 114 K. The wastegate valve could be gradually opened by stepping-up the speed of the engine. The ratio of wastegate flow to the turbine housing gas flow is near 30% for the high rotational speeds and loads. Therefore, the exhaust gas passes through the wastegate channel and the velocity reaches 538 m/s for 2° opening of the wastegate valve. Simulation results show that 1.5 mm decreasing the wall thickness of the volute wall causes 30 Kelvin higher temperature in the turbine housing wall. According to the results of the simulation, the impeller specific work of high gas flow condition was observed to be up to 2.5 times of low mass flow rate operation. Furthermore, the specific amount of gas heat transfer at a closed wastegate condition is significantly higher in comparison to the high gas flow rate and open wastegate condition. In addition, the results show that at low speed and closed wastegate condition, 15 percent of the specific heat transfer occurs before the turbine wheel.