Experimental Comparison Of Different Water Supply Modes For The Flow Facility

The flow standard device is the basis of flow measurement and testing technology.The flow stability of the flow standard device’s water supply system is a researchhotspot in the field of flow measurement and testing. This paper contains thefollowing research work about the water supply system of the flow device.1. Systematically analyzed the definition and evaluation methods of flow stability,and the principle and characteristics of different pressure control modes for watersupply system.2. Analyzed the main factors influencing the flow stability from the two aspects ofwater pressure fluctuations and pipe network resistance.3. Reformed the pipes and the measure and control equipment of flow standarddevice in Shenyang metrology institute. Tested the flow stability of severalwater-supply modes such as the overflow water tower supply mode, the pumpspeed controlling supply mode, the frequency converter supply mode and thepump speed controlling (with surge tank) supply mode through experiment. Thedata indicated that the pump speed control supply mode and the water towersupply mode got nearly the same level of flow stability, and the surge tank had alimited effect on the flow stability. In the case of without water tower or surgetank, the flow stability got from pump speed control supply mode was better than0.1%. It is found through the experiment that on the low flow rate, the flowstability would be improved by opening the by-pass pipe to let the pump work inthe range of the optimum working frequency. The data also shows that within theflow rate range of1000:1, single pump can reach the flow stability of0.2%.