Improving the Accuracy and Reducing the Cost of Measuring Airflow in Turbine Engine Ground Tests

摘要

The Arnold Engineering Development Center (AEDC) initiated an airflow measurement technique investigation to address turbine engine test requirements with respect to both airflow measurement accuracy and costs. The effort encompassed development of a research test cell to serve as an airflow calibration facility and testing of a series of venturi and bellmouth models. The experiments included a repeat of experiments conducted in 1961 that form the basis for the Engine Test Facility (ETF) critical flow venturi flow coefficients. The tests provided a verification of the original measurements, substantiating the current AEDC flow coefficients. In addition, the experiments included a parametric investigation of venturi flow coefficient sensitivities to flow quality, geometric, and installation parameters. These sensitivities provided information for evaluating airflow measurement accuracy provided by venturis installed in ETF test facilities and the basis for accuracy improvements. Finally, the investigation progressed to the development of the bellmouth as an alternative airflow measurement device that avoids the costs intrinsic in the venturi methodology.