Short Duration Aerodynamic Performance Measurement Of Low Reynolds Turbine And Investigation Of Transient Effect

Experimental investigation plays a key role in gas turbine technology. But it exists some disadvantages in the conventional long-duration turbine test facility such as high construction/operation expense, long experiment time, so the researchers begin to develop short-duration test facility from the 1980s. This new experiment equipment requires much less expense and experiment time, and can simulate various environments of specific heat capacity, Reynolds number or Mach number easily, so it's used widely in investigation of internal flow aerothermody-namics.The institute of engineering thermophysics (IET) constructs the blowdown short-duration turbine test facility and takes a series of aerodynamics or heat transfer turbine experiments by it. Aerodynamics performance experiment data of a Low Reynolds turbine (LReT) are presented and the influence on short-duration experiment results of transient effect is analyzed. The main content in this paper is listed as follows:1. In order to explorer the flow mechanics in LReT and validate the LReT design concept, aerodynamics performance measurements of LReT are conducted. Aerodynamics data of LReT at design point and offdesign condition of various Reynolds number are presented. According to the experimental results, LReT is designed well and suitable for working in the high altitude low Reynolds number condition.2. Different from long-duration test facility, the short-duration facility can not provide stable flow field. The changes of flow parameters will influence the experimental results consequently and make some difference between the results of short-duration test and long-duration test, so the conception of transient effect is introduced to describe this influence. Transient effect harms the accuracy and creditability of short-duration test in some degree and limit it as the mechanics investigation platform. 3. The unsteady processes of changes of pressure ratio and rotational speed are simulated by CFD and normalized pressure rate (P|^) and normalized rotational speed rate (ω|^) are defined to evaluate the change pace of pressure ratio and rotational speed. According to the CFD results analysis, the relationships between influence of transient effect and (P|^) or (ω|^) are linear. Generally, (P|^) and (ω|^) can be limited to be very small by the method of quasi steady time and the error caused by transient effect will be no more than 0.3% accordingly.4. The correction equations of turbine efficiency and mass flow are presented. For a certain test, the test results can be corrected according to experimental data and fitting coefficients derived from CFD results.