Investigation of flow through the two-stage orifice

Abstract

In the field of engineering, understanding the flow characteristics of an orifice is key to accurately controlling pressure or flow; however, the transitional flow characteristics of the two-stage orifice has not been studied. The value of the discharge coefficient parameterizing the two-stage orifice flow equation is primarily based on that of the single classic orifice; however, this assumption leads to significant errors, because of the different numbers in the sudden contraction structure. Through theoretical derivation, the flow equations difference between the two-stage orifice and single classic orifice was compared and analyzed. Combing theoretical analysis, Computational Fluid Dynamics (CFD) simulation and experimental measurement, the transitional flow characteristics of the twostage orifice were investigated using mineral oil. The comparison results of the three parts are essentially consistent. In this paper, the discharge coefficient and the pressure drop over the twostage orifice were primarily focused on Reynolds numbers between 900 and 1700. In comparison with the single orifice, the results show that under the same dimensions (d = 3 mm), the discharge coefficient of the two-stage orifice is greater, and the transitional flow state of the two-stage orifice is different from that of the single orifice. Additionally, the pressure drop of the two-stage orifice is less than that of the single orifice under the same volume flow rate. The prestage cylindrical hole slows the changing trend of the flow field parameters, and the second-stage orifice with smaller diameter is mainly responsible for the pressure loss. The current research provides important support for accurate pressure and flow control of the two-stage orifice, and the role of the prestage cylindrical hole can also be a good reference in the structure design of micro-orifices.

Sector orifice with a correlation-based analysis

“…The 𝐶 and Δ𝑝 analysis for the discharge coefficient are taken into consideration for a two-stage orifice. For the examination of a 3 mm diameter orifice, which provides better control than a single orifice, the mineral oil is classified as a fluid with a Reynolds number in the range of 900 to 1700 [16]. Numerical analyses of crescent orifice considered for optimizing the geometrical parameter based on flow analysis are reported [17].…”

Effect of sleeve orifices ratio on flow performance and hydrodynamic noise in the two-stage sleeve control valve

“…29 The guiding plate with orifices can avoid the gap jet flow and improve the flow stability of valve downstream. 30 Gao et al 31 study the flow characteristics of two-staged orifices. In comparison with the single orifice, the results show that the discharge coefficient and the transitional flow state of the two-stage orifice are different from that of the single orifice.…”