压力水头

自压软管沿程压力水头分布研究

Study on pressure head distribution along the gravity flexible hoses

通过摄动方法得到一系列关于水头展开式的偏微分方程，用有限差分法进行求解，获得了压力水头的随机描述，并计算其均值和方差。

The equations are solved by finite difference method and the mean and variance of pressure head are determined from its random expression .

根据计算结果可知，局部地方的压力水头最高值出现在降雨结束2d左右，往后整个边坡非饱和区地下水压力水头全面下降，逐渐恢复原状。

The pressure water head keeps on increasing for 1 to 2 days owing to groundwater infiltration when the end of rainfall in some areas of slope .

在此基础上，定义了降比r和压比G，根据r的大小，讨论了均匀坡毛管压力水头的分布；

This paper also defines the reducing ratio to be r and the pressure ratio to be G , and according to the value of discusses the distribution of lateral pressure head on the uniform slope .

压力水头下开裂混凝土渗透特性试验研究

Experimental research on cracked concrete permeability under water pressure

本文建立了适合地下滴灌条件下以压力水头为因变量的二维土壤水分运动数学模型。

Based on the principle of soil water dynamics , a two-dimension mathematical model of soil water movement is presented for subsurface irrigation .

在同一坡度和压力水头下，滴孔的流量偏差率随铺设长度的增加而增大；

With the same slope and pressure head , the flow deviation ratio of drip holes increases with the length of hoses paved ;

以压力水头为因变量的数学模型可以模拟供水压力和灌水器特性对灌溉效果的影响。

A mathematical model whose variable is water head can simulate the effects of water head and properties of subsurface irrigation pipe on irrigation .

根据深孔的体型边界综合满足等允许压力水头和等允许空化数的条件，提出了一种按临界落差设计的原则。

Based upon the condition of both equal pressure head and equal cavitation index , a ″ critical fall ″ design method is put forward .

结果表明出流量及压力水头对于拟合参数来说都是敏感的且增加压力后参数的敏感系数也相应增加；

The results showed that outflow and pressure head data were both sensitive to the parameters fitted and the sensitive coefficients increased when pressure increased .

对多孔管压力水头变化进行了定性分析，引入了多孔管的特性系数M。

According to qualitative analysis about the changes of pressure heads of the porous-hose , the coefficient M for the characteristics of porous hoses is introduced .

边坡上部压力水头受影响的水平深度在80~100m，深部渗流场几乎不受降雨入渗影响；

At top of slope , the horizontal affected range of pressure head is 80-100 m , and there is scarcely any change in the deep of slope ;

压力水头对滴灌系统的灌水质量影响很小，这为低水头滴灌提供了理论依据。

Low pressure trickle irrigation is based on the little effect of pressure on the quality of drip irrigation system . Low pressure trickle irrigation is popular with farmers .

两个支管水锤压力水头都是由支管末端瞬态操作阀门前向支管首端分水口处递减分布。

Water hammer pressure head of two trunk pipes show decreasing distribution from the end of branch pipe with Transient operation before valve to water distribution outlet of the first side for branch pipe .

土壤水分持留曲线指的是土壤体积水分含量与压力水头之间的关系，在研究土壤水分流动和溶质运移中有着非常重要的作用。

Soil water retention curve refers to the relationship between volumetric water content and pressure head , which plays a very important role in solving the problems of water flow and solute transport in soil .

在田间滴灌管网常见的布置情况下，如灌水器间距、灌水器类型、毛管管径、毛管长度等在各种可能的变动范围内，模拟毛管上平均压力水头所在位置的范围。

Average pressure position of drip line is determined by programming on conditions that the distance of emitter , the styles of emitter the diameter of drip line and the length of drip line vary within probable range .

对均匀坡度单条双向毛管支管最佳位置进行分析表明，在大多数情况下，上坡毛管上的最小压力水头与下坡毛管上的最小压力水头是不同的；

By analyzing the best nonlinear station position of the uniform grade single scroll bidirectional capillary tube , the difference was existed between the minimum pressure of the uphill capillary and the minimum pressure of the downhill capillary under the most conditions .

影响均匀度的原因有压力水头的偏差，滴头的制造精度，温度的差异，滴头的间距，不良水质引起的堵塞和系统维修情况等。

The impact of the evenness of the reasons there is pressure on the head of the aberrations in the manufacture of precision emitter , the temperature difference between the emitter spacing , poor water quality caused by congestion and system maintenance , and so on .

这种泵效率高、经济、简单、体积小，可压送压力水头高达250英尺的水量。江水源热泵套管式换热器换热效率的实验研究和模拟分析

This pump is efficient , economical , simple and quite small . It can be built to furnish almost any amount of water against pressure heads of up to 250 feet . Experiment and Simulation on Heat Transfer Efficiency of Double-pipe Heat Exchanger for River Water-source Heat Pump

研究方法：隧道水压力受地下水水头损失和地下水与衬砌接触面积的双重影响，据此在调整岩溶隧道水头折减系数的基础上，分析隧道水压力模式。

Research method : because the water pressure is influenced double by head loss and contact area between karst water and tunnel lining , based on regulate decrease coefficient of head on karst tunnel , analysis model of water pressure on tunnel .

在考虑渗流效应时，巷道开挖后巷道周围的孔隙水压力随开挖面的水头压力减小而下降，下降区间数值呈现带状。

In considering the seepage effect , the pore water pressure around tunnel decreased with the drop of water pressure in the cutting surface .