大气压力对细水雾灭火系统泵组流量特性及效率的影响

柱塞泵是泵组式细水雾灭火系统的关键部件,它是细水雾喷头实施喷雾的供水源和压力驱动源.为研究大气压力,特别是高海拔低气压环境对柱塞泵流量特性及效率的影响,通过在合肥及拉萨两地的对比试验,给出了环境压力与柱塞泵流量特性及效率的关系.结果表明,大气压力减小使柱塞泵的流量减小,因此,在高原低气压环境下使用柱塞泵,应采用增加柱塞泵进口压力的措施,以保证泵组式细水雾灭火系统的设计性能;不同大气压力下泵组的效率无明显变化,即大气压力对泵组的效率无明显影响.

Influence of the ambient pressure on the flux and efficiency of the pump supplying water mist fire-extinguishing system

The present paper is aimed to introduce our experimental study on the influence of the ambient pressure in places with different altitudes on the flux and efficiency of the pumping set in a water-mist fire-extinguishing system, particularly at the lower ambient pressures at high-attitudes. For the above study purposes, we have carried out comparative experiments in Hefei and Lhasa, where the ambient pressures are 101 kPa and 65 kPa respectively. The flux characteristics of the piston pump were also studied under different flux pressure conditions in the two places by changing the influx and outflux pressures ofthe pump in the comparative experiments. While testing the energy efficiency of the pumping sets by measuring the electric power of the pump and calculating the effective power, we have taken it as the key part for the pump set to supply water-mist for the fire-extinguishing system. To ensure the efficiency of the pumping set, attention has also been paid to the quality and efficiency of the piston, which exerts high-pressure water for water-mist nozzle to ensure the atomization of the fuel. Since the performance of the pump set directly influences the water supply for the nozzle and the spray intensity and other parts of the pumping set, it has also to ensure the proper working conditions which may in final analysis affect the fire-extinguishing efficiency of the water-mist influx. The influx rate of piston pump decreases as the ambient pressure decreases, as is shown in our tests in Lhasa, whose influx rate is just about 87% of that at Hefei. If the absolute influx pressures of the piston pump in the two places are the same, the outflux rates are almost the same. That is to say, the ambient pressures mainly affect the inlet absolute pressure and thus the flux of the piston pump changes consequently. Therefore, increasing the inlet pressure of the piston pump under the lower ambient pressure conditions should be expected to ensure the efficiency of the water mist fire-extinguishing system. In addition, the results of our comparative experiments prove no evident variation of the efficiency of the pump set under different ambient pressures, namely, no remarkable change was found with the energy efficiency of the pump sets due to the effects of ambient pressures