Effect of Pipe-Diameter Ratio on Flow Characteristics of Impinging Jet from Coaxial Circular Pipe

The traditional orifice discharge formula used to estimate the flow rate through a leak opening at a pipe wall often produces inaccurate results. This paper reports an original experimental study in which the influence of orifice-to-pipe diameter ratio on leakage flow rate was investigated for several internal/external flow conditions and orifice holes with different shapes. The results revealed that orifice-to-pipe diameter ratio (or pipe wall curvature) indeed influenced the leakage flow, with the discharge coefficient ( C d ) presenting a wide variation (0.60–0.85). As the orifice-to-pipe diameter ratio decreased, the values of C d systematically decreased from about 12% to 3%. Overall, the values of C d also decreased with β (ratio of pressure head differential at the orifice to wall thickness), as observed in previous studies. On the other hand, orifice shape, main pipe flow velocity, and external medium (water or air) all had a secondary effect on C d . The results obtained in the present study not only demonstrated that orifice-to-pipe diameter ratio affects the outflow, but also that real scale pipes may exhibit a relevant deviation of C d from the classical range (0.61–0.67) reported in the literature.

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Coupling Analysis of Fluid-Structure Interaction and Flow Erosion of Gas-Solid Flow in Elbow Pipe

Advances in Mechanical Engineering ◽

10.1155/2014/815945 ◽

2014 ◽

Vol 6 ◽

pp. 815945 ◽

Cited By ~ 3

Author(s):

Hongjun Zhu ◽

Hongnan Zhao ◽

Qian Pan ◽

Xue Li

Keyword(s):

Erosion Rate ◽

Structural Changes ◽

Fluid Structure Interaction ◽

Fluid Phase ◽

Diameter Ratio ◽

Pipe Diameter ◽

Discrete Phase Model ◽

Two Phase ◽

Fluid Structure ◽

Structure Interaction

A numerical simulation has been conducted to investigate flow erosion and pipe deformation of elbow in gas-solid two-phase flow. The motion of the continuous fluid phase is captured based on calculating three-dimensional Reynolds-averaged-Navier-Stokes (RANS) equations, while the kinematics and trajectory of the discrete particles are evaluated by discrete phase model (DPM), and a fluid-structure interaction (FSI) computational model is adopted to calculate the pipe deformation. The effects of inlet velocity, pipe diameter, and the ratio of curvature and diameter on flow feature, erosion rate, and deformation of elbow are analyzed based on a series of numerical simulations. The numerical results show that flow field, erosion rate, and deformation of elbow are all sensitive to the structural changes and inlet condition changes. Higher inlet rate, smaller curvature diameter ratio, or smaller pipe diameter leads to greater deformation, while slower inlet rate, larger curvature diameter ratio, and larger pipe diameter can weaken flow erosion.

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Investigation of air-water two-phase flow characteristics in a 25.4 mm diameter circular pipe

Progress in Nuclear Energy ◽

10.1016/j.pnucene.2021.103813 ◽

2021 ◽

pp. 103813

Author(s):

Dewei Wang ◽

Shanbin Shi ◽

Yucheng Fu ◽

Kyle Song ◽

Xiaodong Sun ◽

...

Keyword(s):

Two Phase Flow ◽

Flow Characteristics ◽

Circular Pipe ◽

Phase Flow ◽

Two Phase

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Flow and Energy Loss Downstream of Rectangular Sharp-Crested Weirs for Free and Submerged Flows

Journal of Fluids Engineering ◽

10.1115/1.4052049 ◽

2021 ◽

Author(s):

Mahmud R. Amin ◽

Nallamuthu Rajaratnam ◽

David Z. Zhu

Keyword(s):

Energy Loss ◽

Flow Regime ◽

Analytical Study ◽

Flow Characteristics ◽

Turbulent Jets ◽

Flow Regimes ◽

Impinging Jet ◽

Relative Energy ◽

Surface Flow ◽

Upper Stage

Abstract This work presents an analytical study of the flow and energy loss immediately downstream of rectangular sharp-crested weirs for free and submerged flows, using the theory of plane turbulent jets and the analysis of some relevant studies. The flow regimes downstream of the sharp-crested weir is characterized as the impinging jet and surface flow regimes. Based on the flow characteristics and the downstream tailwater depths, each flow regime is further classified, and the relative energy loss equation is developed. It is found that significant energy loss occurs for the regime of supercritical flow and the upper stage of impinging jet flow. The energy loss for the submerged flow regime is minimal.

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CFD SIMULATION OF EROSION BY PARTICLE COLLISION IN U-BEND AND HELICAL TYPE PIPES

Journal of the Serbian Society for Computational Mechanics ◽

10.24874/jsscm.2020.14.02.01 ◽

2020 ◽

Vol 14 (2) ◽

pp. 1-13

Author(s):

Mohammad Sheikh Mamoo ◽

Ataallah Soltani Goharrizi ◽

Bahador Abolpour

Keyword(s):

Mass Flow ◽

Mean Curvature ◽

Particle Density ◽

Fluid Velocity ◽

Diameter Ratio ◽

Solid Particles ◽

Pipe Diameter ◽

Design Parameters ◽

Curvature Radius ◽

Rate Of Penetration

Erosion caused by solid particles in curve pipes is one of the major concerns in the oil and gas industries. Small solid particles flow with a carrier liquid fluid and impact the inner wall of the piping, valves, and other equipment. These components face a high risk of solid particle erosion due to the constant collision, which may result in equipment malfunctioning and even failure. In this study, the two-way coupled Eulerian-Lagrangian method with the Oka erosion and Grant and Tabakoff particle-wall rebound models approach is employed to simulate the liquid-solid flow in U-bend and helical pipes using computational fluid dynamics. The effects of operating parameters (inlet fluid velocity and temperature, particle density and diameter, and mass flow rate) and design parameters (mean curvature radius/pipe diameter ratio) are investigated on the erosion of these tubes walls. It is obtained that increasing the fluid velocity and temperature, particle mass flow and particle density increase the penetration rate, particle diameter affects the rate of penetration, and increasing mean curvature radius/pipe diameter ratio decreases the rate of penetration.

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