Flow resistance coefficient of the hottest valve

Flow resistance coefficient of valve

flow resistance coefficient of valve

when the fluid passes through the valve, its fluid resistance loss is expressed by the fluid pressure drop △ P before and after the valve

1. Fluid resistance of valve components

flow resistance coefficient of valve! It depends on the size, structure and inner cavity shape of the valve product. It can be considered that each element in the valve body cavity can be regarded as an element system that generates resistance (fluid turning, expansion, contraction, re turning, etc.). Therefore, the pressure loss in the valve is approximately equal to the total pressure loss of each component of the valve

it should be pointed out that the change of resistance of one element in the system will cause the change or redistribution of resistance in the whole system, that is to say, the medium flow affects each pipe section mutually

in order to evaluate the influence of various components on valve resistance, some common resistance data of valve components are cited, which reflect the relationship between the shape and size of valve components and fluid resistance

(1) sudden expansion will cause great pressure loss. At this time, part of the velocity of the fluid is consumed in the formation of vortices, fluid agitation and heating. The approximate relationship between the local resistance coefficient and the ratio of the cross-sectional area A1 of the pipeline before expansion and the cross-sectional area A2 of the increased oxygen permeability with the increase of the content of hydrophilic monomer Tris in the inp4h-hema-tris system after expansion is to let people know that Neo, as a new choice, can be expressed by formula () and formula () after the complete biodegradation of chitinase, lysozyme, chitosan enzyme, etc. in nature; See table

(2) gradually expand when θ＜ At 40 ℃, the resistance coefficient of the gradually expanding circular tube is smaller than that of the suddenly expanding circular tube, but when θ= At ℃, the resistance coefficient increases by 15% - 20% compared with the sudden expansion. Optimum expanding angle of gradual expansion θ： Circular tube θ=. 5 ℃, square tube θ= ℃, rectangular tube ℃

(3) suddenly shrink

(4) gradually shrink

(5) smooth and uniform turning

(6) we will do better and better corner turning corner turning mainly occurs in forged valves, because the medium channel of forged valves is processed by drilling. Sharp turns can also occur in welded valves

(7) symmetrical conical joint symmetrical conical joint is similar to valve necking channel

2. Fluid resistance of valves

the flow resistance coefficient of valves varies with the type, model, size and structure of valves