Flow Characteristic Investigation Of STC Control Valve

The Control-Valve is a key part of the Sequential Turbocharging(STC) system, and the choice of the equal valve is the guarantee for normal work of the system. There has no criterion for choosing the STC Control-Valve yet in our country. This paper describes the demands of the control of the STC Control-Valve and provides some criterions for choosing valves according to the special working environment. Besides that, this paper also studies on the computation methods of choosing the size of the valves, and then processes the computation of the STC Control-Valves of a STC diesel engine.In the investigation, the three-dimensional models of the valves were built by FLUENT software. The valves included the gas valve, the air valve and the bypass valve. In the computation, the k-εturbulence model and SIMPLE algorithm were used in the models. Through computation, we got the distribution of the flow field of the valve systems. According to the results, we had got the recover curve of total pressure, we also had got the curve of the turbulent kinetic energy and the loss of total pressure. Through analyzing of the results, we chose the STC Control-Valves, meanwhile, the method for computation the valves was checked.The pressure in the exhaust pipe was changing acutely during the gas valve opening process, and this resulted in the imbalance between the turbochagers. The imbalance may bring the surge to the turbochargers. This paper analyzed the transient flow field in the exhaust pipe when the valve was opening, and the computation results were consistent with the data in the documents. All of these provide the criterion for designing and improving the pipe system, besides that, the research also found the basis for deeper investigation.