Analysis of Flow Field in Large Disc Valves
Pang Dongqing,
Gao Zhenbing,
Sun Yicai
Issue:
Volume 1, Issue 2, June 2019
Pages:
15-27
Received:
29 August 2019
Accepted:
23 September 2019
Published:
7 November 2019
Abstract: The formula Q = Qmax×2000q/qmax-1 is used to describe the relationship between the flow rate Q and the valve opening angle (q/qmax-1 ) in the large disc valve [1], . In this paper, the simplified Navier-Stokes equation [2-4] is applied to the analysis of flow field in large disc valves. It also includes the use of Bernoulli equation [2-4] to determine the pressure conditions at both ends of the valve based on the specified flow rate Q of the valve. This is the first time, the universal formulas and images of flow angles for flow lines that satisfy boundary conditions including both ends, two walls, and disc surface flow lines are proposed. In this paper, flow rate, flow velocity and pressure are discussed on the basis of streamlines [2-4]. Because the flow function Y for any flow lines is constant [2], setting Y to be a two-order polynomial of x and y, then prove that it satisfies the flow function equation [2], and according to the definition of the flow function, the two components of the flow velocity, longitudinal and transverse are evaluated as two more simpler polynomial of x and y, for afterwards use. For the disc valve, the flow rate through any lines that passes two points is equal to the difference of the flow function Y values at these two points [2], which proves that the flow function has nothing to do with the y coordinate at the center line of the disc valve. The longitudinal flow rate Q along the disc valve is only related to the longitudinal flow velocity v, so v is obtained according to the flow rate Q at the different valve opening angles q. Finally, the transverse velocity u in disc valve at the different valve opening angles is obtained by using the Navier-Stokes equation and the obtained universal formulas of the flow angles. Finally, analysis of flow field in large disc valves is completed. This is different from the methods [5-9, 11-16] to be widely used software simulation of flow fields, as there is no need to divide the flow field by grids.
Abstract: The formula Q = Qmax×2000q/qmax-1 is used to describe the relationship between the flow rate Q and the valve opening angle (q/qmax-1 ) in the large disc valve [1], . In this paper, the simplified Navier-Stokes equation [2-4] is applied to the analysis of flow field in large disc valves. It also includes the use of Bernoulli equation [2-4] to determ...
Show More
