Numerical Modeling of Pressure Losses Caused by Bends in Pneumatic Conveying Pipeline

2009 ◽  
Author(s):  
Jie Cui
Keyword(s):  
Numerical Modeling ◽  
Pressure Drop ◽  
Flow Pattern ◽  
Pressure Loss ◽  
Pressure Field ◽  
Pneumatic Conveying ◽  
Laboratory Measurements ◽  
Pressure Losses ◽  
Flow Information ◽  
Parametric Studies

Pneumatic conveying pipelines are widely employed in many industries to transport granular solids. Use of bends with various turning radii in these pipelines is mandatory and it is well known that the bends cause a loss of energy which results in an additional pressure drop. The pressure loss associated with various bends in pneumatic conveying pipelines was studied numerically. The numerical modeling results were validated against laboratory measurements, and parametric studies were performed to examine various factors that affect the pressure loss caused by bends in pneumatic conveying pipelines. Since the numerical results supply flow information at every location in the pipeline, the flow pattern and pressure field of air and pellet were resolved in detail to investigate the mechanism of the pressure loss in such systems.

scholarly journals Minor pressure losses for different connections of PP-R and PEX/Al/PEX installation pipes

2019 ◽  
Vol 100 ◽  
pp. 00045
Author(s):  
Kinga Ligaj ◽  
Marcin K. Widomski ◽  
Anna Musz-Pomorska
Keyword(s):  
Reynolds Number ◽  
Numerical Modeling ◽  
Pressure Loss ◽  
Flow Resistance ◽  
Direct Connection ◽  
Laboratory Measurements ◽  
Local Pressure ◽  
Pressure Losses ◽  
Numerical Research

This paper presents results of laboratory and numerical research concerning determination of water flow resistance through three types of two-way connection of polymer installation pipes: PP-R 20x3.4 mm and PEX/Al/PEX 16x2.0 mm. The following fittings were applied: the direct connection, pipe union and coupler, allowing to test six measurement variants. The laboratory measurements of pressure loss for the tested pipes connections were performed for variable Reynolds number, from approx. 5000 to 50000. The numerical modeling allowing to assess the distributions of velocity of flow and turbulence intensity were performed using FLUENT, Ansys Inc. modelling software. The relations between determined values of minor pressure loss and coefficients of local pressure losses and type of pipes connection, direction of flow as well as the value of Reynolds number were observed. The applied nonparametric statistics, combined with multi comparison, showed that in most cases of analyzed connections, besides the pipe union, the observed differences in pressure losses for various directions of flows are statistically significant for p = 0.05.

Perforated Plate Pressure Losses With Improved Inlet and Outlet Flow Hole Features

2003 ◽  
Author(s):  
Kirkland D. Broach ◽  
Michael E. Conner ◽  
Jeffery L. Norrell ◽  
Carter E. Lunde
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
Perforated Plate ◽  
Small Scale ◽  
Factors Affecting ◽  
Pressure Losses ◽  
Outlet Hole ◽  
Outlet Flow ◽  
Hole Geometry ◽  
The Impact

This paper describes the tests and studies performed to better understand the geometric factors affecting pressure loss in a perforated plate. In this study, the impact of a specific perforated plate flow hole geometry on pressure drop was investigated. The methodology established in this paper to investigate this hole geometry can be extended to other components with orifice type perforated plates. To reduce the pressure drop of the perforated plate, various fundamental hole geometries, including edge chamfers and edge radii, were considered. Results from various edge treatments are provided in this study, including separate effects for inlet and outlet hole geometries. Specific trends, such as the effect of increasing edge geometries on the hydraulic losses, are presented. Additionally, a correlation between small-scale and full-scale pressure loss coefficients was found and is defined.

scholarly journals Annular frictional pressure losses for drilling fluids

2020 ◽  
pp. 1-19
Author(s):  
Arild Saasen ◽  
Jan David Ytrehus ◽  
Bjørnar Lund
Keyword(s):  
Pressure Loss ◽  
Parallel Plate ◽  
Fluid Model ◽  
Axial Flow ◽  
Measured Data ◽  
Drilling Fluids ◽  
Laboratory Measurements ◽  
Model Approximation ◽  
Pressure Losses ◽  
Shear Rates

Abstract In the paper it is demonstrated how a Herschel-Bulkley fluid model, where the parameters are selected from relevant shear rate range of the flow and are parametrically independent, can be used for pressure loss calculations. The model is found to provide adequate pressure loss predictions for axial flow in an annulus where the inner cylinder does not rotate. It is described how one can simplify a slot model approximation of the annulus pressure loss using the Herschel-Bulkley fluid model (Founargiotakis model). This simplified model gives approximately the same accuracy as does the full Founargiotakis model. It is shown that use of such a parallel plate model gives reasonably good fit to measured data on laminar flow of oil-based drilling fluids if the viscous data are measured at relevant shear rates for the flow. Laboratory measurements indicate that use of the simplified pressure loss model is also valid for turbulent flow. However, the predictions should be adjusted for the surface roughness in the well.

scholarly journals A New Design Model of an MR Shock Absorber for Aircraft Landing Gear Systems Considering Major and Minor Pressure Losses: Experimental Validation

2021 ◽  
Vol 11 (17) ◽  
pp. 7895
Author(s):  
Byung-Hyuk Kang ◽  
Jai-Hyuk Hwang ◽  
Seung-Bok Choi
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Pressure Loss ◽  
Shock Absorber ◽  
Landing Gear ◽  
Design Model ◽  
Pressure Losses ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
Major Loss

This work presents a novel design model of a magnetorheological (MR) fluid-based shock absorber (MR shock absorber in short) that can be applied to an aircraft landing gear system. When an external force acts on an MR shock absorber, pressure loss occurs at the flow path while resisting the fluid flow. During the flow motion, two pressure losses occur: the major loss, which is proportional to the flow rate, and the minor loss, which is proportional to the square of the flow rate. In general, when an MR shock absorber is designed for low stroke velocity systems such as an automotive suspension system, the consideration of the major loss only for the design model is well satisfied by experimental results. However, when an MR shock absorber is applied to dynamic systems that require high stroke velocity, such as aircraft landing gear systems, the minor loss effect becomes significant to the pressure drop. In this work, a new design model for an MR shock absorber, considering both the major and minor pressure losses, is proposed. After formulating a mathematical design model, a prototype of an MR shock absorber is manufactured based on the design parameters of a lightweight aircraft landing gear system. After establishing a drop test for the MR shock absorber, the results of the pressure drop versus stroke/stroke velocity are investigated at different impact energies. It is shown from comparative evaluation that the proposed design model agrees with the experiment much better than the model that considers only the major pressure loss.

scholarly journals Flow pattern and pressure drop for oil–water flows in and around 180° bends

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Paul Onubi Ayegba ◽  
Lawrence C. Edomwonyi-Otu ◽  
Abdulkareem Abubakar ◽  
Nurudeen Yusuf
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Flow Pattern ◽  
Phase Inversion ◽  
Superficial Velocity ◽  
Pressure Losses ◽  
Water Flows ◽  
Oil Water ◽  
Velocity Pressure ◽  
Mixture Velocity

AbstractPressure drop and flow pattern of oil–water flows were investigated in a 19-mm ID clear polyvinyl chloride pipe consisting of U-bend with radius of curvature of 100 mm. The range for oil and water superficial velocities tested was $$0.04 \le U_{{{\text{so}}}} \le 0.950 \;{\text{m/s}}$$ 0.04 ≤ U so ≤ 0.950 m/s and $$0.13 \le U_{{{\text{sw}}}} \le 1.10 \;{\text{m/s}}$$ 0.13 ≤ U sw ≤ 1.10 m/s , respectively. Measurements were carried out under different flow conditions in a test section that consisted of four different parts: upstream of the bend, at the bend and at two redeveloping flow locations after the bend. The result indicated that the bend had limited influence on downstream flow patterns. However, the shear forces imposed by the bend caused some shift flow pattern transition and bubble characteristics in the redeveloping flow section after the bend relative to develop flow before the bend. Generally, pressure gradient at all the test sections increased with both oil fraction and water superficial velocity and there was a sharp change of pressure gradient profile during phase inversion. The transition point where phase inversion occurred was always within the range of $$0.4 \le U_{{{\text{sw}}}} \le 0.54 \;{\text{m/s}}$$ 0.4 ≤ U sw ≤ 0.54 m/s . Pressure losses differed at the various test sections, and the difference was strongly linked to the superficial velocity of the phases and the flow pattern. At high mixture velocity, pressure losses at the redeveloping section after the bend were higher than that at the bend and that for fully developed flows. At low mixture velocity, pressure losses at the bend are higher than in the straight sections. Pressure drop generally decreased with level of flow development downstream of the bend.

scholarly journals Flow Pattern and Pressure Drop for Oil-Water Flows in and around 180° Bends

2020 ◽  
Author(s):  
Paul Onubi Ayegba ◽  
Lawrence C. Edomwonyi-Otu ◽  
Abdulkareem Abubakar ◽  
Nurudeen Yusuf
Keyword(s):  
Pressure Drop ◽  
Pressure Gradient ◽  
Flow Pattern ◽  
Phase Inversion ◽  
Superficial Velocity ◽  
Pressure Losses ◽  
Water Flows ◽  
Oil Water ◽  
Velocity Pressure ◽  
Mixture Velocity

Pressure drop and flow pattern of oil-water flows were investigated in a 19 mm ID clear polyvinyl chloride pipe consisting of U-bend with radius of curvature of 100 mm. The range for oil and water superficial velocities tested were and respectively. Measurements were carried out under different flow conditions in a test section that consisted of four different parts: upstream of the bend, at the bend and at two redeveloping flow locations after the bend. The result indicated that the bend had limited influence on downstream flow patterns. However, the shear forces imposed by the bend caused some shift flow pattern transition and bubble characteristics in the redeveloping flow section after the bend relative to develop flow before the bend. Generally, pressure gradient at all the test sections increased with both oil fraction and water superficial velocity and there was a sharp change of pressure gradient profile during phase inversion. The transition point where phase inversion occurred was always within the range of . Pressure losses differed at the various test sections and the difference was strongly linked to the superficial velocity of the phases and the flow pattern. At high mixture velocity, pressure losses at the redeveloping section after the bend were higher than that at the bend and that for fully developed flows. At low mixture velocity, pressure losses at the bend are higher than in the straight sections. Pressure drop generally decreased with level of flow development downstream of the bend.

Pressure Drop in Horizontal Taper Pipe of Dense-Phase Pneumatic Conveying

2013 ◽  
Vol 291-294 ◽  
pp. 1930-1933
Author(s):  
Guang Bin Duan ◽  
Kun Wang ◽  
Zong Ming Liu
Keyword(s):  
Pressure Drop ◽  
Pressure Field ◽  
Three Dimensional ◽  
Diameter Ratio ◽  
Transmission Power ◽  
Pneumatic Conveying ◽  
Dense Phase ◽  
Dominant Effect ◽  
Engineering Project ◽  
Taper Angle

Experimental research was performed to describe the pressure drop occurring in horizontal taper pipe of dense phase pneumatic conveying, which were widely used in the engineering project. Compressed air was used as transmission power and fly ash as the transport medium. Results showed that the geometric parameters of taper pipe including taper angle and diameter ratio had a dominant effect on the pressure drop of the gas solid flow. In addition, a three-dimensional numerical simulation was performed to show the trend of the pressure field intuitively in the transporting process. And the simulation results of pressure drop were validated by the experimental data.

Numerical Modeling and Parametric Studies of Steam Reformers

2010 ◽  
Vol 41 (3) ◽  
pp. 233-245 ◽  
Author(s):  
C. Ventura ◽  
J. L. T. Azevedo
Keyword(s):  
Numerical Modeling ◽  
Parametric Studies ◽  
Steam Reformers

Modeling of pressure losses on friction in three-layer laminar flows

2003 ◽  
Vol 3 ◽  
pp. 208-219
Author(s):  
A.M. Ilyasov
Keyword(s):  
Pressure Loss ◽  
Gas Flow ◽  
Mutual Influence ◽  
Fluid Model ◽  
Immiscible Liquid ◽  
Laminar Flows ◽  
Pressure Losses ◽  
Flow Parameters ◽  
Interphase Boundaries ◽  
Closing Relations

In this paper we propose a model for determining the pressure loss due to friction in each phase in a three-layer laminar steady flow of immiscible liquid and gas flow in a flat channel. This model generalizes an analogous problem for a two-layer laminar flow, proposed earlier. The relations obtained in the final form for the pressure loss due to friction in liquids can be used as closing relations for the three-fluid model. These equations take into account the influence of interphase boundaries and are an alternative to the approach used in foreign literature. In this approach, the wall and interphase voltages are approximated by the formulas for a single-phase flow and do not take into account the mutual influence of liquids on the loss of pressure on friction in phases. The distribution of flow parameters in these two models is compared.

scholarly journals Turbulence model performance for ventilation components pressure losses

2021 ◽  
Author(s):  
Karsten Tawackolian ◽  
Martin Kriegel
Keyword(s):  
Reynolds Number ◽  
Turbulence Model ◽  
Pressure Loss ◽  
Low Reynolds Number ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Test Case ◽  
Pressure Losses ◽  
Loss Coefficients ◽  
Near Wall

AbstractThis study looks to find a suitable turbulence model for calculating pressure losses of ventilation components. In building ventilation, the most relevant Reynolds number range is between 3×104 and 6×105, depending on the duct dimensions and airflow rates. Pressure loss coefficients can increase considerably for some components at Reynolds numbers below 2×105. An initial survey of popular turbulence models was conducted for a selected test case of a bend with such a strong Reynolds number dependence. Most of the turbulence models failed in reproducing this dependence and predicted curve progressions that were too flat and only applicable for higher Reynolds numbers. Viscous effects near walls played an important role in the present simulations. In turbulence modelling, near-wall damping functions are used to account for this influence. A model that implements near-wall modelling is the lag elliptic blending k-ε model. This model gave reasonable predictions for pressure loss coefficients at lower Reynolds numbers. Another example is the low Reynolds number k-ε turbulence model of Wilcox (LRN). The modification uses damping functions and was initially developed for simulating profiles such as aircraft wings. It has not been widely used for internal flows such as air duct flows. Based on selected reference cases, the three closure coefficients of the LRN model were adapted in this work to simulate ventilation components. Improved predictions were obtained with new coefficients (LRNM model). This underlined that low Reynolds number effects are relevant in ventilation ductworks and give first insights for suitable turbulence models for this application. Both the lag elliptic blending model and the modified LRNM model predicted the pressure losses relatively well for the test case where the other tested models failed.

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