The pumping system and precise mass flow measuring technique for double-inlet wind tunnel test

Inlet test in wind tunnel is a primary approach to evaluate the performance and obtain the characteristic parameters of the inlet. Traditional inlet test technique has some obvious problems, such as low mass flow measurement precision, and inferior test capability, cannot satisfy the inlet tests of different kinds or at different states. The pumping system and mass flow measuring technique of high precision for double-inlet wind tunnel test is established in the FD-12 wind tunnel. The mass flow measuring device using venturi measuring method is introduced to advance the mass flow measurement precision. The mass flow inbreathed by the inlet is increased by means of middle-pressure annular pumping device set at the exit of the mass flow measuring device to satisfy the inlet tests of different kinds or at different states. Two flowpaths were designed to measure and control the mass flow separately, so that the system can satisfy the performance matching and coupling test of double inlets at different states. Wind tunnel tests show that the effectiveness of the measuring device and pumping capability of the pumping device are testified , and the general test capability for inlets of different kinds is also validated. The test results show that the test system is of high measuring precision, strong pumping and wide test capability, and the corresponding technique may satisfy almost all kinds of inlet tests in wind tunnel.