| Abstract | The Engine Laboratory of the National Research Council of Canada has recently participated in a NATO sponsored Uniform Engine Test Program. In this international program, two Pratt & Whitney J57P19W turbojets are being tested in ground-level test beds, indoor and outdoor, and altitude facilities with the objective of rationalizing any performance differences that may appear.
Procedures in the laboratory had to be developed to assess engine airflow, fuel flow, and gross thrust. Airflow was calculated based on total pressure and temperature measurements in an annular section behind the entry bellmouth, and inner and outer wall static pressures. Euel flow was measured with two turbine meters placed in series, and corrected for viscosity and temperature effects. Gross thrust was deduced using the momentum method and scale force measurements.
A rigorous error an lysis was performed with the result that airflow, thrust, and specific fuel consumption could be measured with uncertainties of +0.77%, +0.31%, and +0.52% respectively.
Data comparisons based on rotor speeds, high or low compressor, yielded poor comparisons with two altitude facilities. However, using non-dimensional thrust coefficients as a function of nozzle pressure ratio, the differences were reduced to 0.2%. |
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