Experimental investigation of Pressure Drop/Flow Rate Relationship for Small Aperture Holes for High Viscosity Fluids

2012 ◽  
Author(s):  
Rachna Jain ◽  
Ted Alan Long ◽  
Jasper Lane Dickson ◽  
Scott V. Brown ◽  
Edmond Shtepani
Keyword(s):  
Experimental Investigation ◽  
Pressure Drop ◽  
Flow Rate ◽  
High Viscosity ◽  
Small Aperture ◽  
Rate Relationship ◽  
Drop Flow

A Constitutive Equation for Extensional-Thickening Fluids Flowing Through Porous Media

2002 ◽  
Author(s):  
Paulo R. Souza Mendes ◽  
Moˆnica F. Naccache
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Constitutive Equation ◽  
Flow Rate ◽  
Pore Channel ◽  
Pressure Gradients ◽  
Rate Relationship ◽  
Liquid Behavior ◽  
The One ◽  
Drop Flow

A constitutive relation between the pressure gradient and the seepage velocity has been developed that carries information about the liquid behavior on extension. The relation was developed in two steps. Firstly the pressure drop/flow rate relationship for an ideal pore channel was obtained. Then a capillaric model theory was applied to obtain the sought-for constitutive equation. The proposed relation was validated comparing pressure drop/flow rate results with experimental data obtained in a geometry similar to the one used in the theoretical model. Also, some comparisons with experimental data for a M1 Boger fluid flowing in a model porous medium were performed. The results showed that the proposed relation has good predictions capabilities in a representative range of pressure gradients.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

Performance of a High-Solidity Wells Turbine for an OWC Wave Power Plant

1996 ◽  
Vol 118 (4) ◽  
pp. 263-268 ◽  
Author(s):  
L. M. C. Gato ◽  
V. Warfield ◽  
A. Thakker
Keyword(s):  
Experimental Investigation ◽  
Power Plant ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aerodynamic Performance ◽  
Wave Power ◽  
Wells Turbine ◽  
Guide Vanes ◽  
Turbine Efficiency ◽  
Pressure Distributions

The paper describes an experimental investigation, and presents the results of the aerodynamic performance of a high-solidity Wells turbine for a wave power plant. A monoplane turbine of 0.6 m rotor diameter with guide vanes was built and tested. The tests were conducted in unidirectional steady airflow. Measurements taken include flow rate, pressure drop, torque, and rotational speed, as well as velocity and pressure distributions. Experimental results show that the presence of guide vanes can provide a remarkable increase in turbine efficiency.

Aqua-Ammonia as an Environmentally Acceptable Low Temperature Brine

2011 ◽  
Author(s):  
Alan A. Kornhauser
Keyword(s):  
Energy Efficiency ◽  
Pressure Drop ◽  
Calcium Chloride ◽  
Flow Rate ◽  
Methylene Chloride ◽  
Volume Flow Rate ◽  
Environmental Safety ◽  
High Viscosity ◽  
Frictional Pressure Drop ◽  
Aqua Ammonia

In many industrial processes, cooling with brines is preferable to cooling with an evaporating refrigerant. For medium and high temperatures (above about −35°C/−30°F), aqueous solutions of calcium chloride, sodium chloride, ethylene glycol, propylene glycol, and methanol have typically been used. For very low temperatures (down to about −80°C/-110°F) halocarbon refrigerants methylene chloride and trichloroethylene have generally been used. In recent years, both methylene chloride and trichloroethylene have come under increasingly strict regulation because of their toxicity. While many plants continue to use these brines, most are searching for alternates. This study was begun in response to the needs of a plant that was replacing methylene chloride with aqueous calcium chloride. The high viscosity of the calcium chloride brine caused design and operational problems. The above-mentioned brines, as well as aqua-ammonia, polydimethylsiloxane, and d-limonene, were compared for cost, toxicity, flammability, environmental safety, and energy efficiency. The energy efficiency comparison included comparisons of heat transfer coefficient, mass flow rate, volume flow rate, frictional pressure drop, inertial pressure drop, and pumping power. The comparisons indicated that aqua-ammonia was the best choice as a replacement for methylene chloride and trichloroethylene in some temperature ranges.

A Study on Phase Difference Between Pressure Drop and Flow Rate of Sine Fluctuation in Rectangular Channel

2012 ◽  
Author(s):  
Bao Zhou ◽  
Pu-zhen Gao ◽  
Si-chao Tan ◽  
Jing-da Tian
Keyword(s):  
Experimental Investigation ◽  
Pressure Drop ◽  
Phase Difference ◽  
Flow Rate ◽  
Delay Time ◽  
Rectangular Channel ◽  
Mean Values ◽  
Rate Fluctuation ◽  
Measurement Delay ◽  
Pressure Transmitter

An experimental investigation on fluctuating turbulent flow with different amplitudes, frequencies and mean values of flow rate in a narrow rectangular channel was carried out to determine the phase difference so as to find out real corresponding relationship between pressure drop and flow rate. It is found that the measurement delay time difference between the flow meter and the differential pressure transmitter is not a constant but vary with the different flow rate fluctuation conditions. The phase difference was calculated by a function which is given in this paper and tested by the result of two kinds of nonlinear fit methods, whose results agree well.

scholarly journals Assessment of Different Pressure Drop-Flow Rate Equations in a Pressurized Porous Media Filter for Irrigation Systems

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2179
Author(s):  
Jonathan Graciano-Uribe ◽  
Toni Pujol ◽  
Jaume Puig-Bargués ◽  
Miquel Duran-Ros ◽  
Gerard Arbat ◽  
...  
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Silica Sand ◽  
Rate Equations ◽  
Uncertainty Range ◽  
Head Losses ◽  
Computational Fluid Dynamics Cfd ◽  
Drop Flow

The small open area available at the slots of underdrains in pressurized granular bed filters for drip irrigation implies: (1) the existence of a region with non-uniform flow, and (2) local values of modified particle Reynolds number >500. These flow conditions may disagree with those accepted as valid for common pressure drop-flow rate correlations proposed for packed beds. Here, we carried out detailed computational fluid dynamics (CFD) simulations of a laboratory filter to analyze the results obtained with five different equations of head losses in porous media: (1) Ergun, (2) Darcy-Forchheimer, (3) Darcy, (4) Kozeny-Carman and (5) power function. Simulations were compared with experimental data at different superficial velocities obtained from previous studies. Results for two silica sand media indicated that all equations predicted total filter pressure drop values within the experimental uncertainty range when superficial velocities <38.3 m h−1. At higher flow rates, Ergun equation approximated the best to the observed results for silica sand media, being the expression recommended. A simple analytical model of the pressure drop along flow streamlines that matched CFD simulation results was developed.

Fluid Dynamics of a Partially Collapsible Stenosis in a Flow Model of the Coronary Circulation

1996 ◽  
Vol 118 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Maria Siebes ◽  
Charles S. Campbell ◽  
David Z. D’Argenio
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Coronary Circulation ◽  
Intraluminal Pressure ◽  
Dimensional Changes ◽  
Area Reduction ◽  
Stenosis Severity ◽  
Flexible Wall ◽  
Drop Flow

The influence of passive vasomotion on the pressure drop-flow (ΔP-Q) characteristics of a partially compliant stenosis was studied in an in vitro model of the coronary circulation. Twelve stenosis models of different severities (50 to 90 percent area reduction) and degrees of flexible wall (0 to 1/2 of the wall circumference) were inserted into thin-walled latex tubing and pressure and flow data were collected during simulated cardiac cycles. In general, the pressure drop increased with increasing fraction of flexible wall for a given flow rate and stenosis severity. The magnitude of this effect was directly dependent upon the underlying stenosis severity. The diastolic ΔP-Q relationship of severe, compliant models exhibited features of partial collapse with an increase in pressure drop at a decreasing flow rate. It is concluded that passive vasomotion of a normal wall segment at an eccentric stenosis in response to periodic changes in intraluminal pressure causes dimensional changes in the residual lumen area which can strongly affect the hemodynamic characteristics of the stenosis during the cardiac cycle. This mechanism may have important implications for the onset of plaque fracture and the prediction of the functional significance of a coronary stenosis based on quantitative angiogram analysis.

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