The Development Of Fast Response Aerodynamic Probe Based On Digital Signal Processing

The internal flow mechanism of turbomachinery is one of the most difficult issues of complex flow, which has attracted researchers'attention for many years. High-frequency responding measurement technology is necessary to investigate the internal flow by experiments, due to the three dimensional flow, unsteadiness, vortex interaction, shock wave structures, flow instability, strong adverse pressure gradient, interaction between rotor and stator existing in the internal flows. The investigation of high-frequency responding measurement technology thus is an important project, and the related researches are published in the Journal of Turbomachinery every year.As a main measurement method of experimental research on turbomachinery, fast response measurement techniques based on pneumatic multi-hole probe and micro-pressure sensor is an international hot issue. In this paper, a new measurement method integrating fast response aerodynamic probe and DSP(digital signal processing) is carried out. Zero drift, linearity trimming, dynamic mass test data storage, adjustable gain range etc. are realized in the method which make the fast response measurement technique more systematic, intelligent, and convenient. Some work on measurement accuracy, measurement range, pneumatic eigenfrequency, blockage effects is done. This study is expected to raise the level of measurement technology of turbomachinery internal flow.The dissertation is organized as follows:1. Probe design, construction and calibration. Calculating the eigenfrequency of the probe.2. A Computational Fluid Dynamics analysis was conducted to assess the blockage effect when the probe intrudes into the duct.3. Digital Signal Processor was used to make the measurement system systematic, intelligent and convenient.4. Experiments were conducted in the cascade and axial compressor using the pneumatic probe.The results show that:The internal design of the probe led to a sensor cavity eigenfrequency of 11.5kHz. The probe will block the area if it is intruded into the duct between two vanes and influence the distribution of the mass flow of the ducts and. There will be a shift in the entire pressure distribution around the probe, towards the suction side of the vane if the probe is intruded. A new measurement method integrating fast response aerodynamic probe and DSP (digital signal processing) is carried out. Zero drift, linearity trimming, dynamic mass test data storage, adjustable gain range etc. are realized in the method.