Single-Phase and Two-Phase Flow Through Thin and Thick Orifices in Horizontal Pipes

Abstract

Two-phase flow pressure drops through thin and thick orifices have been numerically investigated with air–water flows in horizontal pipes. Two-phase computational fluid dynamics (CFD) calculations, using the Eulerian–Eulerian model have been employed to calculate the pressure drop through orifices. The operating conditions cover the gas and liquid superficial velocity ranges Vsg = 0.3–4 m/s and Vsl = 0.6–2 m/s, respectively. The local pressure drops have been obtained by means of extrapolation from the computed upstream and downstream linearized pressure profiles to the orifice section. Simulations for the single-phase flow of water have been carried out for local liquid Reynolds number (Re based on orifice diameter) ranging from 3 × 104 to 2 × 105 to obtain the discharge coefficient and the two-phase local multiplier, which when multiplied with the pressure drop of water (for same mass flow of water and two phase mixture) will reproduce the pressure drop for two phase flow through the orifice. The effect of orifice geometry on two-phase pressure losses has been considered by selecting two pipes of 60 mm and 40 mm inner diameter and eight different orifice plates (for each pipe) with two area ratios (σ = 0.73 and σ = 0.54) and four different thicknesses (s/d = 0.025–0.59). The results obtained from numerical simulations are validated against experimental data from the literature and are found to be in good agreement.

Volumetric velocity measurements in restricted geometries using spiral sampling: a phantom study

“…If the shape of the restriction is circular and sharp-edged, which is fulfilled for the current setup, the presumed maximum velocity ‫ݒ‬ ௩ , ௫ in vena contracta can be estimated from the reference flow (Q), the orifice area (A), and a correction factor C d (coefficient of discharge), adopted for thickplate geometries [40,41]:…”

“…The correction factor C d was extracted from ref [41], and for this particular geometry was found to be…”

Design of flow control devices in steam-assisted gravity drainage (SAGD) completion

“…If the flow is subcritical, the flow rate is related to the pressure drop across the restriction. However, if the flow is critical, the pressure drop is related only to upstream pressure as reduction in downstream pressure cannot be communicated upstream (Darby 2001;Janssen 1967;Ramamurthi and Nandakumar 1999;Roul and Dash 2012). To optimize a restriction-based FCD, understanding the critical/subcritical boundary and the fluid flow pattern across the restriction is of absolute importance.…”

Dynamic Behaviour of Flow through Multi-Stage Restricting Orifices

“…Based on Buckingham Π-theorem, the relationship between the above variables can be written in dimensionless form as, 2 Re, , , , 0.5…”

“…Accurate determination of flow characteristics through these restrictions especially orifices is important for industrial operations such as control measures in HVAC, quality control in food processing industry, metering of high viscous liquids and calibrating tools in metrology of liquid and gas flows [1]. Single orifices are also used to enhance uniformity of flow distribution and exchange of heat and mass as applicable in premixed combustion [2]. When orifices are also used as flow restriction devices for the sake of pressure control, flowrate control or both, this may result in high hydraulic losses, severe erosion in the presence of solid particles; cavitation in liquid flows, choking is gas flows in addition to noise and vibration.…”