Discharge Coefficient for Venturi Flowmeter With Short Laying Length

1982 ◽  
Vol 104 (4) ◽  
pp. 463-467
Author(s):  
Masahiro Inoue
Keyword(s):  
Experimental Data ◽  
Potential Flow ◽  
Total Pressure ◽  
Discharge Coefficient ◽  
Empirical Equation ◽  
Static Pressure ◽  
Computational Technique ◽  
One Dimensional ◽  
Streamline Curvature ◽  
Venturi Flowmeter

This paper presents a method for predicting the discharge coeffcient for a venturi flowmeter with a short laying length where the static pressure is not uniform at the throat due to streamline curvature. The discharge coefficient is determined by combining potential flow calculations and one-dimensional viscous flow considerations. For the potential flow, an accurate computational technique proposed by the author is used to calculate the pressure at the throat tap by assuming that the total pressure is equal to the average one at the throat. The average total pressure is related to the inlet pressure by use of a generalized empirical equation based on one-dimensional considerations. Validity of the method is verified by comparison with published experimental data for short venturi flowmeters.

Preston-Static Tubes for the Measurement of Wall Shear Stress

1994 ◽  
Vol 116 (3) ◽  
pp. 645-649 ◽  
Author(s):  
Josef Daniel Ackerman ◽  
Louis Wong ◽  
C. Ross Ethier ◽  
D. Grant Allen ◽  
Jan K. Spelt
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Convenient Method ◽  
Pipe Flow ◽  
Total Pressure ◽  
Static Pressure ◽  
Shear Stresses ◽  
Streamline Curvature ◽  
Syringe Needle ◽  
Wall Shear

We present a Preston tube device that combines both total and static pressure readings for the measurement of wall shear stress. As such, the device facilitates the measurement of wall shear stress under conditions where there is streamline curvature and/or over surfaces on which it is difficult to either manufacture an array of static-pressure taps or to position a single tap. Our “Preston-static” device is easily and conveniently constructed from commercially available regular and side-bored syringe needles. The pressure difference between the total pressure measured in the regular syringe needle and the static pressure measured in the side-bored one is used to determine the wall shear stress. Wall shear stresses measured in pipe flow were consistent with independently determined values and values obtained using a conventional Preston tube. These results indicate that Preston-static tubes provide a reliable and convenient method of measuring wall shear stress.

Some aspects of the flow in S-shaped diffusing ducts

1994 ◽  
Vol 98 (978) ◽  
pp. 305-310 ◽  
Author(s):  
S. C. M. Yu ◽  
E. L. Goldsmith
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Axial Length ◽  
Total Pressure ◽  
Static Pressure ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Group 13 ◽  
Duct Geometry

The circular cross-sectional Royal Aerospace Establishment (RAE) 2129 S-shaped intake diffusing duct series, shown in Fig. 1, which has an offset of the inlet and exit centerline of 0·3 and 0·45 of the axial length of the duct, was designed at the RAE (Bedford) and tested at British Aerospace Filton, at low forward speeds (freestream Mach no. range from 0 – 0·2 but a range of duct inlet Mach numbers up to choking speeds) in the last two decades to fulfil the objectives of collecting systematic experimental data on engine face pressure recovery, total pressure flow distortion and wall static pressures for computational fluid dynamics validation. Some of the measurements have been presented, as for example, by Willmer, Brown & Goldsmith. The measurements from one version of Model 2129 (the 0·3 length offset S-duct geometry) have been used to compare with calculated results from a number of CFD programs, as for example, by Anderson, Horton and by the AGARD Working Group 13. The series of comparison also highlight the need for measurements other than the engine face total pressure and wall static pressure which have already been made.

Basic Analysis of Tip Leakage Mixing Loss

2007 ◽  
Author(s):  
Weiwei Shao ◽  
Lucheng Ji ◽  
Ronghui Cheng
Keyword(s):  
Simple Model ◽  
Total Pressure ◽  
Discharge Coefficient ◽  
Static Pressure ◽  
Tip Clearance ◽  
Blade Surface ◽  
Blade Loading ◽  
Tip Leakage ◽  
Pressure Loss Coefficient ◽  
Total Pressure Loss Coefficient

A simple model for tip leakage mixing loss of unshrouded blades for compressible flow is presented. The work draws ideas, is based on the theoretical analysis of the loss by Denton. Relationship for computing the loss is derived, in terms of blade surface static pressure, chordwise distribution of tip clearance, discharge coefficient and total pressure loss coefficient in the tip region. Parameter studies reveal average level and chordwise distribution of the above factors’ contribution to the loss. Results clearly indicate the governing variables and mechanisms which drive tip leakage mixing loss. Combined clearance and blade loading study is developed, most excitedly, an important parameter is put forward, which can reflect synthetically the influence of blade loading and tip clearance distribution on the tip leakage mixing loss.

Generalized Flow Across an Abrupt Enlargement

1976 ◽  
Vol 98 (3) ◽  
pp. 327-332 ◽  
Author(s):  
R. P. Benedict ◽  
J. S. Wyler ◽  
J. A. Dudek ◽  
A. R. Gleed
Keyword(s):  
Experimental Data ◽  
Compressible Fluid ◽  
Total Pressure ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Pressure Variation ◽  
Generalized Solutions ◽  
Dimensionless Numbers ◽  
The Face ◽  
Total Pressure Ratio

Generalized solutions are developed for the flow across an abrupt enlargement. Three cases are considered, namely; an incompressible fluid, a subsonic compressible fluid, and a compressible fluid in supercritical flow. All characteristic quantities are given in the form of dimensionless numbers which are readily useful such as: the loss in terms of the total pressure ratio across the step, the pressure recovery in terms of the static pressure ratio across the step, and the pressure variation across the face of the step in terms of the throat-to-wall pressure ratio. All theoretical equations are verified by new experimental data, and design curves and tables are given for various area ratios operating at various pressure ratios.

A Method for Predicting Annular Diffuser Performance with Swirling Inlet Flow

1981 ◽  
Vol 23 (3) ◽  
pp. 107-112 ◽  
Author(s):  
A. H. Elgammal ◽  
A. M. Elkersh
Keyword(s):  
Experimental Data ◽  
Computer Program ◽  
Potential Flow ◽  
Frictional Coefficient ◽  
One Dimensional ◽  
Analytical Technique ◽  
Theoretical Predictions ◽  
Annular Diffuser ◽  
Swirled Flow ◽  
Good Agreement

A method for predicting the performance of annular diffusere with swirled flow at inlet is presented. The method is based on the assumptions of one-dimensional potential flow using a frictional coefficient parameter to account for friction losses. Theoretical predictions are in good agreement with available experimental data for a variety of annular diffuser geometries. In addition a computer program has been developed, allowing the present analytical technique to be readily applied to the design of any annular diffuser with swirled flow at inlet.

Mass Transfer in Liquid in an Apparatus with Mobile Packing. Application of a Dispersion Model

1993 ◽  
Vol 58 (5) ◽  
pp. 1078-1086
Author(s):  
Zdeněk Palatý
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Empirical Equation ◽  
Dispersion Model ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients

The paper deals with the mass transfer in a liquid on a plate with mobile packing. A procedure has been suggested which enables estimation of the mass transfer coefficients from experimental data considering the dispersion flow of the liquid. The results obtained from the desorption of CO2 from water are presented graphically and in the form of empirical equation.

Numerical investigations on the effect of volute casing treatment for performance augmentation in a centrifugal fan

2021 ◽  
pp. 095440622110341
Author(s):  
Manjunath L Nilugal ◽  
K Vasudeva Karanth ◽  
Madhwesh N
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Casing Treatment ◽  
Sliding Mesh ◽  
Optimum Configuration

This article presents the effect of volute chamfering on the performance of a forward swept centrifugal fan. The numerical analysis is performed to obtain the performance parameters such as static pressure rise coefficient and total pressure coefficient for various flow coefficients. The chamfer ratio for the volute is optimized parametrically by providing a chamfer on either side of the volute. The influence of the chamfer ratio on the three dimensional flow domain was investigated numerically. The simulation is carried out using Re-Normalisation Group (RNG) k-[Formula: see text] turbulence model. The transient simulation of the fan system is done using standard sliding mesh method available in Fluent. It is found from the analysis that, configuration with chamfer ratio of 4.4 is found be the optimum configuration in terms of better performance characteristics. On an average, this optimum configuration provides improvement of about 6.3% in static pressure rise coefficient when compared to the base model. This optimized chamfer configuration also gives a higher total pressure coefficient of about 3% validating the augmentation in static pressure rise coefficient with respect to the base model. Hence, this numerical study establishes the effectiveness of optimally providing volute chamfer on the overall performance improvement of forward bladed centrifugal fan.

A Theoretical Analysis of CO2 Absorption in Sun Versus Shade Leaves

1978 ◽  
Vol 100 (1) ◽  
pp. 20-24 ◽  
Author(s):  
R. H. Rand
Keyword(s):  
Experimental Data ◽  
Quantitative Estimate ◽  
Geometric Model ◽  
Model Parameters ◽  
Co2 Absorption ◽  
Temperature Model ◽  
Spongy Mesophyll ◽  
One Dimensional ◽  
Mesophyll Tissue ◽  
Shade Leaves

A one-dimensional, steady-state, constant temperature model of diffusion and absorption of CO2 in the intercellular air spaces of a leaf is presented. The model includes two geometrically distinct regions of the leaf interior, corresponding to palisade and spongy mesophyll tissue, respectively. Sun, shade, and intermediate light leaves are modeled by varying the thicknesses of these two regions. Values of the geometric model parameters are obtained by comparing geometric properties of the model with experimental data of other investigators found from dissection of real leaves. The model provides a quantitative estimate of the extent to which the concentration of gaseous CO2 varies locally within the leaf interior.

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