Sharif Digital Repository

This paper presents a control oriented model for predicting turbine major variables in a turbocharged spark ignition engine. The turbine is simulated as a two-nozzle chamber where the pressure ratio over the two nozzles is not the same. A convex nonlinear estimation algorithm is formulated to determine the relation between these pressure ratios. The new model is experimentally validated with transient and steady state data collected from a 1.7 liter gasoline engine. The results show the new model can predict the turbine mass flow with an average error of 1.4%. In addition, the application of the turbine model is illustrated for the design of a nonlinear observer to estimate the turbocharger... 

In this paper, numerical and experimental investigation of the performance and internal flow field characteristics of the twinentry radial inflow turbine under full and partial admission conditions are presented. The turbine is tested on a turbocharger test facility, which was developed for small and medium size turbochargers. The flow pattern in the volute and impeller of a twin-entry turbine is analyzed using fully three-dimensional viscous program. The computational performance results are compared with the experimental results, and good agreement is found. The flow field at the outlet of the turbine is investigated using a five-hole pressure probe. The tests are performed for both full... 

This paper presents numerical and experimental investigation of the performance and internal flow field characteristics of twin-entry radial inflow turbines at full and extreme partial admission conditions. The turbine is tested on a turbocharger test facility, which was developed for small and medium size turbochargers. Experimental results show that the lowest efficiency corresponds to extreme conditions. Therefore, flow field analyzing is employed to consider these conditions. The flow pattern in the volute and impeller of a twin-entry turbine is analyzed using an in-house fully three-dimensional viscous flow solver. The computational performance results are compared with the experimental... 

In this paper, a numerical and experimental investigation of the performance and internal flow field characteristics of the twin-entry radial inflow turbine under full and partial admission conditions are presented. The turbine is tested on a turbocharger test facility which was developed for small and medium size turbochargers. The flow pattern in the volute and impeller of a twin-entry turbine is analyzed using a fully three-dimensional viscous program. The computational performance results are compared with the experimental results, and good agreement is found. The flow field at the outlet of the turbine is investigated using a five-hole pressure probe. Numerical and experimental results... 

In the conceptual design phase of a turbocharger, where emphasis is mainly on parametric studies, before manufacturing and tests, a generalized and robust model that applies over a wide range properly, is unavoidable. 12The critical inputs such as turbine maps are not available during the conceptual design phase. Hence, generalized turbine models use alternate methods that work without any supplementary tests and can operate over wide ranges. One of the common and applicable modeling methods in design process is 'Dimensionless Modeling' using the constant coefficient scaling (CCS). This method can almost predict the turbine characteristics at the design point. However, at off-design... 

In this paper, the performance of a turbocharger twin-entry radial inflow turbine is investigated analytically and experimentally under steady state, full and partial admission conditions. In this modeling, the mass flow rate, pressure ratio and efficiency of the turbine are assumed unknown. The turbine geometry and the inlet total pressure and temperature are known, hence, the turbine performance characteristics can be obtained. In the turbocharger laboratory, performance characteristics of the turbine are determined, measuring the main parameters for various operating conditions. Comparing the model and experimental results shows good agreement. Also, considering the effect of test...