The Study On Orifice’s Local Resistance Adjacent Impact In Pressure Water Pipe

In the traditional hydraulic calculation, calculated the total local head loss according to the principle of superposition of resistance,but simply according to the superposition principle to calculate the total resistance usually do not tally with the actual local head loss.Through studying, the interactions between the deformation is one of the causes of this phenomenon. In order to reveal the phenomenon of mutual influence between the deformation, to explore the mechanism of mutual influence, correction formula of total local head loss, in this paper, we will choose orifice plate what installed in the pressure pipe as the research object,combined with experimental study, the method of numerical simulation and theory analysis, to study the interactions between the deformation phenomena.In this paper, through the experimental study method,we measured total local resistance coefficient of the orifice plate when installing multiple orifice in the pressure pipe,then the experimental value of total local resistance coefficient of the orifice plate was compared with the theoretical calculation values. By analyzing the causes of differences between test value and the calculated value, reveal the mutual influence between the orifice plate deformation parts. Experimental research shows that when calculating the total local head loss, the mutual influence between deformation must be considered and we need use adjacent effect coefficient to modify the traditional calculation formula. By the method of numerical simulation research, studied the interaction coefficient changing rule with orifice plate thickness to diameter ratio, aperture ratio, and the relative distance. According to the flow field calculation results, reveal influence adjacent of the resistance mechanism. Through dimensional analysis research method, established the function relation between the adjacent effect coefficient, in combination with the results of numerical simulation applied numerical analysis method to obtain adjacent influence coefficient calculation formula.Finally use adjacent influence coefficient to modify traditional local head loss formula and the revised formula was tested. These research are expected to provide the reference for calculating total local head loss accurately, enrich and perfect the pipeline hydraulic calculation theory of local head loss.