Testing high-pressure sensors

J. Muchow, A. Kretschmann, R. Henn, K. Skrobanek, S. Finkbeiner, H.-R. Krauss, Influence of process variation on the functionality of a high pressure sensor, Design, Test, Integration and Packaging of MEMS/MOEMS, DTIP 2002, SPIE Proc 4755, Bellingham WA, USA, 2002, 143-148. 

Fig. 7.4.8 shows the results of endurance testing of a metal thin-film high-pressure sensor with the design shown in Fig. 7.4.7. Typical deviations from the ideal characteristic can be seen. The sensor has been tested in a gasoline direct injection car for 162000 km. The deviation is shown for pressures up to 140 bar and temperatures between —40 and 140 °C. Hysteresis can be seen for increasing and decreasing pressures at each measuring temperature. The maximum deviation of about 0.3% FSD demonstrates the long-term stability of the sensor package design and the thin-film technology.

For wall temperature measurements 10 thermocouples are fixed on the heated part of the tube. Entrance and exit manifolds have pressure taps and thermocouples to measure the fluid pressure and temperature. A differential pressure sensor is also placed between the test section inlet and outlet. Heating the test section is performed by means of a low voltage U (0 - 2 V), high intensity 7(100-1800 A) power supply. 

Figure 3 shows the test section and instrumentation. Ten wall temperatures on the tube external surface were measured with 0.5 mm diameter calibrated type E thermocouples electrically insulated from the aluminium. Fluid inlet and outlet temperatures were measured with 1 mm diameter calibrated type K thermocouples. Cah-bration was carried out with a Rosemount 162-CE platinum thermometer. Due to the high thermal conduchvity of the aluminium and the low thickness of the tube walls the measured temperature is very close to the wall temperature in contact with the fluid (the difference less than 0.01 K). The inlet fluid pressure was measured with a calibrated Rosemount type 11 absolute pressure sensor. Two calibrated differential pressure sensors measured the pressure loss through the test section. A Rosemount Micro-motion coriolis flowmeter was used to... 

Passive core make-up water tank is used so as to eliminate high pressure safety injection pumps. Transient characteristic research of core make-up water tank in the case of small LOCA were performed. The break sizes are 2, 6, 12, 18, 30 mm respectively. Thermal hydraulic behaviors of pressurizer and draining flow rate measurement from core make-up water tank to primary coolant system following small LOCA were researched and carried out in the test. A total of 80 sensors were used to measure temperatures, liquid level and flow rate. 

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