Two-Phase Flow Through a Relief Valve Discharging Into a Water Filled Pipe

2004 ◽  
Author(s):  
L. I. Ezekoye ◽  
T. J. Matty ◽  
S. R. Swantner
Keyword(s):  
Thermal Properties ◽  
Single Phase ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Minimal Effect ◽  
Water Application ◽  
Flow Conditions ◽  
Relief Valve ◽  
Two Phase ◽  
Flow Through

Relief valves provide overpressure protection of components and systems. To properly size them, one needs to know the fluid conditions upstream and downstream, the physical and thermal properties of the fluids at the postulated relieving conditions, a model that can be used to predict the capacity and the geometry of the inlet and outlet conditions. However, in many applications, it is not uncommon that some of the information needed to properly size relief valves may be missing. For example, there may not be information on the inlet and outlet pipe configuration, which may influence the flow conditions. For single-phase flows, neglecting inlet and outlet piping configurations may have minimal effect on the capacity. However, for fluids that are slightly subcooled with a potential for flashing, the effect may be significant. The problem is magnified by the fact that, unlike single phase flows where the ASME standard provides a method for sizing single phase relief valve capacity, there is no standard model for sizing two-phase flow relief capacity. In this paper, we present the sizing of a relief valve for a slightly subcooled water application with attached piping using the ASME and the OMEGA methods to illustrate the differences in their estimates.

An Analytical Model for Prediction of Two-Phase (Noncondensable) Flow Pump Performance

1985 ◽  
Vol 107 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Okitsugu Furuya
Keyword(s):  
Analytical Method ◽  
Single Phase ◽  
Two Phase Flow ◽  
Control Volume ◽  
Model Development ◽  
Oil Well ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Pressurized Water

During operational transients or a hypothetical LOCA (loss of coolant accident) condition, the recirculating coolant of PWR (pressurized water reactor) may flash into steam due to a loss of line pressure. Under such two-phase flow conditions, it is well known that the recirculation pump becomes unable to generate the same head as that of the single-phase flow case. Similar situations also exist in oil well submersible pumps where a fair amount of gas is contained in oil. Based on the one dimensional control volume method, an analytical method has been developed to determine the performance of pumps operating under two-phase flow conditions. The analytical method has incorporated pump geometry, void fraction, flow slippage and flow regime into the basic formula, but neglected the compressibility and condensation effects. During the course of model development, it has been found that the head degradation is mainly caused by higher acceleration on liquid phase and deceleration on gas phase than in the case of single-phase flows. The numerical results for head degradations and torques obtained with the model favorably compared with the air/water two-phase flow test data of Babcock and Wilcox (1/3 scale) and Creare (1/20 scale) pumps.

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

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Manmatha K. Roul ◽  
Sukanta K. Dash
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Orifice Diameter ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Horizontal Pipes ◽  
Flow Through

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.

scholarly journals Experimental Investigation of the Vertical Upward Single- and Two-Phase Flow Pressure Drops Through Gate and Ball Valves

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Ammar Zeghloul ◽  
Hiba Bouyahiaoui ◽  
Abdelwahid Azzi ◽  
Abbas H. Hasan ◽  
Abdelsalam Al-sarkhi
Keyword(s):  
Experimental Investigation ◽  
Pressure Drop ◽  
Single Phase ◽  
Gate Valve ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Pressure Drops ◽  
Flow Pressure

Abstract This paper presents an experimental investigation of the pressure drop (DP) through valves in vertical upward flows. Experiments were carried out using a 1¼″ (DN 32) ball and gate valve. Five opening areas have been investigated from fully open to the nearly fully closed valve, using air with a superficial velocity of 0–3.5 m/s and water 0.05–0.91 m/s. These ranges cover single-phase and the bubbly, slug and churn two-phase flow regimes. It was found that for the single-phase flow experiments, the valve coefficient increases with the valve opening and is the same, in both valves, for the openings smaller than 40%. The single-phase pressure drop increases with the liquid flowrate and decreases with the opening area. The two-phase flow pressure drop was found considerably increased by reducing the opening area for both valves. It reaches its maximum values at 20% opening for the ball valve and 19% opening for the gate valve. It was also inferred that at fully opening condition, the two-phase flow multiplier, for both valves, has been found close to unity for most of the tested flow conditions. For 40 and 20% valve openings the two-phase multiplier decreases in the power-law with liquid holdup for the studied flow conditions. Models proposed originally for evaluating the pressure drop through an orifice in single-phase and two-phase flows were also applied and assessed in the present experimental data.

Acoustical Characteristics of Single and Two-Phase Horizontal Pipe Flow Through an Orifice

2017 ◽  
Author(s):  
S. P. C. Belfroid
Keyword(s):  
Multiphase Flow ◽  
Single Phase ◽  
Two Phase Flow ◽  
Jet Noise ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Choked Flow ◽  
Flow Through

In this work, the acoustic effects of horizontal air-water flow through an orifice are investigated experimentally. Single phase flow (air) and two-phase flow (air and water) tests are performed for two sets of orifices. One set of straight edged and one set of upstream rounded orifices. For each set, the diameters of the orifices were 2, 5, and 10mm, with a thickness of 5 mm. The two-phase flow is generated by injecting water at a rate of 0 to 40 g/s to air in a pipe with diameter of 25 mm. The air rate is fixed in the range from 5.8 to 14 g/s, where the upstream pressure varies from 1.5 to 4 bar at ambient temperature. Unsteady pressure fluctuations are recorded at two upstream and two downstream position. The valve noise standard NEN-EN-IEC (60534-8-3, 2011) for dry gas is assessed by means of experimental data in dry conditions at fixed air mass flow rate. Predictions of sound power spectra by means of the standard are found to be more accurate compared to those obtained following Reethof & Ward (1986), also in conditions of a choked orifice. In case of multiphase flow already at very low liquid fractions of much less than 1%, the standard is no longer valid. The frequency spectrum is no longer determined by the jet noise but starts to be dominated by low frequency general multiphase flow. The Strouhal number based on the jet conditions is an order lower than Sr = 0.2 indicating process variations rather than jet noise. Furthermore, at choking conditions the further expansion which occurs in single phase flow is likely different at multiphase flow. For non-choked flow, the standard can be adapted using multiphase mixture properties. This does lead to a good prediction. However at choked conditions, this method fails.

scholarly journals Numerical simulation of air–water two–phase flow in vertical pipe using k-ε model

2015 ◽  
Vol 4 (1) ◽  
pp. 61 ◽  
Author(s):  
Ali Sanati
Keyword(s):  
Two Phase Flow ◽  
Numerical Data ◽  
Phase Flow ◽  
Gas Velocity ◽  
Flow Conditions ◽  
Empirical Correlations ◽  
Vertical Pipe ◽  
Air Velocity ◽  
Two Phase ◽  
Flow Through

Two-phase flow exists mostly in pipes and is of substantial importance in pipeline industry. Numerical data are presented in this paper for water and air velocity in two-phase flow through vertical circular channel using both K-ε model and empirical correlations. In order to investigate the pressure distribution for various flow conditions, two-phase flow was considered through two vertical pipes with different lengths and the same diameters. Moreover, we studied flow entering from below and getting out from top of the pipe. Results obtained in this study have been analyzed with experimental data, showing that the average void fraction rises with increasing inlet gas velocity and drops with increasing inlet water velocity. Also results show that Hassan & Kabir method is the most appropriate approach in comparison with the others.

Critical Review of Stabilized Nanoparticle Transport in Porous Media

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Xiaoyan Meng ◽  
Daoyong Yang
Keyword(s):  
Porous Media ◽  
Steady State ◽  
Single Phase ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Flow Conditions ◽  
Nanoparticle Transport ◽  
Two Phase ◽  
Transport In Porous Media

Over the past few decades, due to the special features (i.e., easily produced, large-surface-area-to-volume ratio, and engineered particles with designed surface properties), nanoparticles have not only attracted great attentions from the oil and gas industry but also had various applications from drilling and completion, reservoir characterization, to enhanced oil recovery (EOR). As sensors or EOR agents, thus, fate and behavior of nanoparticles in porous media are essential and need to be investigated thoroughly. Nevertheless, most of the published review papers focus on particle transport in saturated porous media, and all of them are about steady-state flow conditions. So far, no attempts have been extended to systematically review current knowledge about nanoparticle transport in porous media with single-phase and two-phase flow systems under both steady-state and unsteady-state conditions. Accordingly, this review will discuss nanoparticle transport phenomena in porous media with its focus on the filtration mechanisms, the underlying interaction forces, and factors dominating nanoparticle transport behavior in porous media. Finally, mathematical models used to describe nanoparticle transport in porous media for both single-phase flow and two-phase flow under steady-state and transient flow conditions will be summarized, respectively.

Effect of Porous Wettability on the Bubble Penetrability and Gas-Liquid Separation Character

2016 ◽  
Author(s):  
Hongxia Chen ◽  
Yuying Yan
Keyword(s):  
Two Phase Flow ◽  
Critical Diameter ◽  
Phase Flow ◽  
Flow Conditions ◽  
Metal Mesh ◽  
Two Phase ◽  
Self Compatibility ◽  
Flow Through ◽  
Micro Structures ◽  
Fundamental Conclusion

To micro-structures of porous materials, the capillary force which is deeply affected by wettability plays an important role. In this paper, directly oxidation method and functionalization by trichloro (1H, 1H, 2H, 2H-perfluorooctyl) - silane are used to modify metal mesh wettability and superhydrophilic and superhydrophobic copper meshes are fabricated. Super-hydrophilic mesh can block bubbles from flowing through, while the superhydrophobic mesh can hold a column of liquid by counteracting gravity which is defined as a self-compatibility of meshes in this paper. As reported in the previous studies, the mesh with micro-pores can modulate two phase flow pattern to enhance heat transfer. In the present study, the dynamic principle of bubbles as they flow through meshes with different wettabilities is studied. A mathematical model between the critical diameter and flow conditions is developed. A fundamental conclusion for the modulation theory of two phase flow in porous structures can be reached.

Sign in / Sign up

Export Citation Format

Share Document