Estimation of the Extended Turbine Maps for a Radial Inflow Turbine 2010-01-1234
Characterization of radial turbine performance is usually represented by turbine characteristics maps. These maps illustrate the relationship between the most representative variables which describe the system behavior.
Many times, due to design constrains available in these test beds, it is not possible to get measurements of the different variables at different turbine rotational speeds over a wide range of expansion ratios. Sometimes this represents a problem when an appropriate engine simulation must be carried out due to the lack of reliable information to run the simulation in operation points where there are no available turbine data. Although an extrapolation could be done using mathematical methods, there are no physics behind which assures an acceptable confidence in the new generated information.
The present paper develops a physics based method for the extrapolation of the radial turbine maps to zones where there is no experimental information.
This method takes into account the definition of the turbine specific diameter as a function of the representative variables illustrated in the maps in order to get a relationship that allows expressing the corrected mass flow against known information, geometric, thermodynamic and specific data and as a function of the expansion ratio. The efficiency is extrapolated by an expression developed from the definition of turbine total to static efficiency and the consideration of velocity triangles.
Results are compared against experimental information and it is found that there is a good agreement between theoretical and test data.