摘要
该文在室内无风状态下,开展了两种小模型消防水炮在不同仰角,不同工作压力下的射流轨迹测量试验。基于单水滴空气中飞行的轨迹计算,采用指数增长形式的空气阻力模型,提出仅含1个待定系数b的射流轨迹预测方法,计算了各个工况下几种系数b取值的射流轨迹。以各个测量点的射流轨迹高度与计算轨迹的高度之差,其算术平均值越小,标准偏差?越小为约束条件,获得预测模型中待定系数b的合适取值,并将该合适b值下计算的射程、射高与实验值对比。结果表明直流式消防水炮b值取0.01,导流式水炮b值取0.08能获得很好的预测精度,试验值与计算值对比,直流式水炮的测点高差算术平均值小于0.25 m,射程预测误差小于1.3%,水射流的射高预测误差小于1.2%,导流式水炮测点高差算术平均值小于0.3 m,射程误差小于2.98%,射高误差小于4.7%。该文的方法可用于开展远射程消防水炮的射程预估。
Two types of small model fire water monitor were experimentally studied indoor with no wind condition. Using the theodolite, the trajectories of fire water monitors were measured with different working pressures and different jet angles. Based on calculating the single droplet flying in the air, and the exponential growth air drag force model, a method is put forward to predict the trajectories that have one undetermined coefficient b. The trajectories are calculated under different operating conditions and with several b values. The smallest arithmetic mean value of every jet height difference between calculating and observing and the smallest standard deviation ？ are used as constraint conditions to get the suitable coefficient b. The calculating range and height of trajectory are compared with the experiment data. The results show that good predict accuracy is obtained when b is 0.01 for straight-flow fire water monitor and b is 0.08 for stream-guidance fire water monitor. Comparing with the experiment data, the average height difference is less than 0.25 m, the errors of range and height prediction are less than 1.3% and 1.2% respectively for straight-flow fire water monitor. As for the stream-guidance fire water monitor, the average height difference is less than 0.3 m, and the errors of range and height prediction are less than 2.98% and 4.7% respectively. The jet trajectory calculating method in this paper can be used to predict the trajectories of large capacity monitor.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2017年第3期325-330,共6页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金资助项目(51379090)
上海市科技重点攻关项目(13231203200)~~
关键词
消防水炮
射流轨迹
空气阻力模型
射程
无风状态
fire water monitor
jet trajectory
air drag force model
range
calm wind condition
