三级林用消防泵内部流场模拟及分析

林用消防泵在森林防火作业中是一种效率高、应用广泛的灭火装备,泵内流体在湍流运动过程中的各物理参数,如速度、压力、温度等都是随时间与空间而随机变化的,是个随机的非线性过程。为了更好地设计满足复杂条件下的林火迅速扑救的大流量、高扬程、质量轻的便携式林用消防泵,在结构设计的基础上进行了泵内流场模拟,分析了林用消防泵的三级提压工作原理。运用FLUENT软件首次模拟了Q为62,105,175,262和340 L/min工况时的三级林用消防泵内部流场,建立了5种工况三级森林消防泵的整机流域模型,并根据模拟结果预测了泵的扬程。相比其他工况,处于流量Q=175 L/min工况时的整机流场压力分布比较合理,叶轮流域、叶轮蜗壳耦合区域以及蜗壳流体区域的作用效果都比较好,流体流动比较稳定。此外,搭建了水泵性能测试系统,开展了5种流量工况条件下的水泵性能试验,将测试计算结果与模拟预测值进行了对比分析。结果显示,模拟预测的扬程与试验计算扬程基本吻合,表明运用FLUENT软件所建整机流域模型对三级林用消防泵的工作性能模拟预测是可行的。同时,在流量Q=175 L/min时,其射程达到117.68 m,满足便携式林用消防泵的设计要求,可以达到远距离灭火的目的。
Forest fire pump is a kind of firefighting equipment with high efficiency and wide application. The physical parameters of the turbulent flow in the pump, such as velocity, pressure and temperature, change randomly over time and space, and the movement is considered a non-linear stochastic process. The purpose of this study was to design a portable forest fire pump characterized by large flow, high lift, light weight and quick firefighting under complex conditions. The flow field in the pump was simulated based on the structural design and the principle of triple-stage pressure increasing of forest fire pump was analyzed by using flow field simulation method. The flow field of the triple-stage forest fire pump was simulated by using the FLUENT software, and the flow field models were established under five flow rate conditions, i.e., 62, 105, 175, 262 and 340 L/min. The lift of the pump was predicted according to the simulation results. When the flow rate was 175 L/min, the flow field pressure distribution was reasonable, the performance of the impeller basin, impeller volute coupling region and volute fluid region were good, and the fluid flow was relatively stable. The pump performance test system was built and tested under these five flow conditions. By comparing the test results with the simulation values, the results showed the simulated pump lift was similar to the test results. It indicates that it is feasible to use FLUENT software in working performance simulation and prediction of the triple-stage forest fire pump. Meanwhile, the flow rate of 175 L/min and lift of 117.68 m can meet the design requirements of the portable forest fire pump and can achieve the purpose of remote fire extinguishment