Flow Distribution Manifolds

1976 ◽  
Vol 98 (4) ◽  
pp. 654-665 ◽  
Author(s):  
R. A. Bajura ◽  
E. H. Jones
Keyword(s):  
Flow Rate ◽  
Distribution Systems ◽  
Flow Distribution ◽  
Nonlinear Ordinary Differential Equation ◽  
Flow Equation ◽  
Experimental Results ◽  
General Application ◽  
Lateral Branches ◽  
Flow Resistances ◽  
Good Agreement

Flow distribution in the lateral branches of dividing, combining, reverse, and parallel flow manifold systems is studied both analytically and experimentally. Predictions for the flow rates and pressures in the headers of any of the above four basic manifold configurations are obtained from the solution of two first order differential equations involving the flow rate and the pressure difference across headers (pressure-flow equation set), or by the solution of a second order, nonlinear ordinary differential equation involving the flow rate alone (flow distribution equation). Experimental results are presented for various manifold designs having different lateral/header area ratios, lateral flow resistances, and length/diameter ratios. Good agreement is obtained between the analytical and experimental results. Dimensionless parameters which affect flow distribution are identified and discussed with respect to the generalized coefficients of the analytical model. The present method of analysis is proposed for general application in evaluating the performance of flow distribution systems.

Heat Transfer in an LTV Falling Film Evaporator: A Theoretical and Experimental Analysis

1968 ◽  
Vol 90 (2) ◽  
pp. 201-210 ◽  
Author(s):  
J. E. Kroll ◽  
J. W. McCutchan
Keyword(s):  
Heat Transfer ◽  
Mathematical Models ◽  
Flow Rate ◽  
Experimental Analysis ◽  
Experimental Results ◽  
Falling Film ◽  
Film Evaporator ◽  
Good Agreement

Two slightly differing mathematical models were developed to describe the heat transfer in the long tube vertical falling film process. The process was investigated experimentally with a 3/4 in. dia tube for various lengths up to 13 ft, for flow rate Reynold’s numbers from 1000 to 13000, for temperature differences of the order of 20 deg F, and for vacuum conditions down to 160 deg F. A comparison of theoretical and experimental results was made and was found to be in good agreement; that is, within 10 percent.

Low-power micro-fabricated liquid flow-rate sensor

2015 ◽  
Vol 7 (9) ◽  
pp. 3981-3987 ◽  
Author(s):  
Wen-Chi Lin ◽  
Mark A. Burns
Keyword(s):  
Low Power ◽  
Water Flow ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Experimental Results ◽  
Flow Sensors ◽  
Flow Rates ◽  
Rate Sensor ◽  
Good Agreement

We have constructed micro-fabricated flow sensors that can measure water flow rates of 0.1 to 2.0 gallons per minute (GPM), and the experimental results we obtained are in good agreement with those from COMSOL simulations.

Experimentally Validated Computational Fluid Dynamics Model for a Data Center With Cold Aisle Containment

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Sami A. Alkharabsheh ◽  
Bahgat G. Sammakia ◽  
Saurabh K. Shrivastava
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Rate ◽  
Data Center ◽  
Flow Distribution ◽  
Temperature Measurements ◽  
Experimental Measurements ◽  
Air Conditioner ◽  
Cfd Model ◽  
Good Agreement

This paper presents the results of an experimentally validated computational fluid dynamics (CFD) model for a data center with fully implemented fan curves on both the servers and the computer room air conditioner (CRAC). Both open and contained cold aisle systems are considered in this study. This work is divided into sections for the baseline system (prior to installing containment) calibration and the fully contained cold aisle system calibration and leakage characterization. In the open system, the fan curve of the CRAC unit is extracted from the manufacturer data, while the fan curve of the load banks is obtained through experimental measurements. The experimental results are found to be in good agreement with the average model predictions. In the fully contained cold aisle system, a detailed containment CFD model is developed based on experimental measurements. The model is validated by comparing the flow rate through the perforated floor tiles and the rack inlet temperatures with the experimental measurements. The CFD results are found to be in good agreement with the experimental data with an average relative error between the measured and computed flow rate of approximately 6.7%. Temperature measurements are used to calibrate the sources of leakage in the containment and rack mounting rails. The temperature measurements and the CFD results agree well with an average difference of less than 1 °C. This study provides important modeling guidelines for data centers. In order to predict the performance of contained cold aisle systems flow distribution, it is crucial that physics based models of fan curves, server internal resistances, detailed rack models, and other design details are all accurate and experimentally verified.

An Experimental Study on Externally Pressurized Supersonic Gas Thrust Bearings

1985 ◽  
Vol 107 (1) ◽  
pp. 122-127 ◽  
Author(s):  
Yutaka Miyake ◽  
Takehiko Inaba ◽  
Naoshige Kubo ◽  
Jun-ichi Takeoka
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Load Capacity ◽  
Experimental Results ◽  
Static Characteristics ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
Theoretical Predictions ◽  
New Type ◽  
Good Agreement

Externally pressurized supersonic gas thrust bearings whose generation of load capacity is substantially independent of the viscosity of working fluids, have been proposed and analyzed by the authors. This report presents the experimental results of the static characteristics of this new type of bearings. The experimental results including load capacity, stiffness, mass flow rate, and pressure distributions in the bearing clearance, generally show a good agreement with the theoretical predictions and verify the validity of this new bearing. The effect of an orifice to improve the stiffness is also examined. Some problems which should be solved to put the bearing in practical use are pointed out.

Numerical Modeling of Steady Inspiratory Airflow Through a Three-Generation Model of the Human Central Airways

1997 ◽  
Vol 119 (1) ◽  
pp. 59-65 ◽  
Author(s):  
F. Wilquem ◽  
G. Degrez
Keyword(s):  
Flow Behavior ◽  
Flow Distribution ◽  
Reynolds Numbers ◽  
Experimental Investigations ◽  
Generation Model ◽  
Kirchhoff’S Laws ◽  
Flow Configurations ◽  
Lateral Branches ◽  
Moody Diagram ◽  
Good Agreement

Two-dimensional steady inspiratory airflow through a three-generation model of the human central airways is numerically investigated, with dimensions corresponding to those encountered in the fifth to seventh generations of the Weibel’s model. Wall curvatures are added at the outer walls of the junctions for physiological purposes. Computations are carried out for Reynolds numbers in the mother branch ranging from 200 to 1200, which correspond to mouth air breathing at flow rates ranging from 0.27 to 1.63 liters per second. The difficulty of generating grids in a so complex configuration is overcome using a nonoverlapping multiblock technique. Simulations demonstrate the existence of separation regions whose number, location, and size strongly depend on the Reynolds number. Consequently, four different flow configurations are detected. Velocity profiles downstream of the bifurcations are shown to be highly skewed, thus leading to an important unbalance in the flow distribution between the medial and lateral branches of the model. These results confirm the observations of Snyder et al. and Tsuda et al. and suggest that a resistance model of flow partitioning based on Kirchhoff’s laws is inadequate to simulate the flow behavior accurately within the airways. When plotted in a Moody diagram, airway resistance throughout the model is shown to fit with a linear relation of slope −0.61. This is qualitatively in good agreement with the experimental investigations of Pedley et al. and Slutsky et al.

Coke Deposition Effect on the Flow Distribution Characteristics of Kerosene Under Supercritical Pressure

2016 ◽  
Author(s):  
H. R. Huang ◽  
H. W. Deng ◽  
G. Q. Xu ◽  
Z. X. Jia ◽  
Y. C. Fu
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Total Mass ◽  
Flow Distribution ◽  
Supercritical Pressure ◽  
Experimental Results ◽  
Coke Deposition ◽  
Axial Position ◽  
System Pressure

Performed experiments have studied the effect of coke deposition on the characteristics of flow distribution of aviation kerosene RP-3 at supercritical pressure. The whole experiment is divided into two steps: 1) making a coke tube; 2) paralleling the coked tube and a regular one with the same scale and observing the flow distribution status in different system pressure and total mass flow rate. The experimental results indicated that the deposition of coke made a great difference on the flow distribution of fuel. Based on experimental results, it’s demonstrated that the percentage of total mass flow rate in coke-free tube increases to 68.5%. Further analyses reveal the fact that the total mass flow rate has nearly no impact on flow distribution and the system pressure also influence the distribution very little. What’s more, the amount of coke vs axial position and total amount of coke in coked tube are mentioned in this paper, which is benefit in analysis of flow distribution.

Adsorption of hexavalent chromium by crosslinked chitosan–iron(III) in an air-lift reactor

2015 ◽  
Vol 73 (4) ◽  
pp. 857-865
Author(s):  
Carla Albertina Demarchi ◽  
Clóvis Antonio Rodrigues
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Adsorption Process ◽  
Breakthrough Curves ◽  
Experimental Results ◽  
Breakthrough Time ◽  
Crosslinked Chitosan ◽  
Air Lift ◽  
Good Agreement

Column experiments were conducted in an airlift reactor containing a certain amount of crosslinked chitosan–iron(III) (Ch-Fe), to examine the effects of adsorbent mass, flow rate, and influent concentrations on Cr(VI) removal. The breakthrough time increased with an increase in Ch-Fe mass, but decreased with an increase in initial Cr(VI) concentration. The exhaustion time decreased with an increase in initial Cr(VI) concentration. The capacity at the breakthrough point increased with an increase in Ch-Fe mass, flow rate, and initial Cr(VI) concentration. The capacity at the exhaustion point increased with an increase in flow rate, but showed no specific trend with an increase in initial Cr(VI) concentration. The bed volumes at breakthrough point increased with an increase in Ch-Fe, flow rate and Cr(VI) concentration. The adsorbent exhaustion decreased with an increase in flow rate and Ch-Fe, but increased with an increase in initial Cr(VI) concentration. Columns with large amounts of Ch-Fe are preferable for obtaining optimal results during the adsorption process. The higher the flow velocity, the better the column performance. The Thomas, Clark and Yoon–Nelson models were applied to the experimental results. Good agreement was observed between the predicted theoretical breakthrough curves and the experimental results.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

A possible modification of groundwater flow equation using coordinate transformations

2014 ◽  
Vol 15 (2) ◽  
pp. 278-287 ◽  
Author(s):  
Abdon Atangana ◽  
Ernestine Alabaraoye
Keyword(s):  
Groundwater Flow ◽  
Prolate Spheroid ◽  
Flow Equation ◽  
Time Space ◽  
Adomian Decomposition ◽  
Iteration Methods ◽  
Groundwater Flow Equation ◽  
Factor Α ◽  
Modified Equation ◽  
Good Agreement

We described a groundwater model with prolate spheroid coordinates, and introduced a new parameter, namely τ the silhouette influence of the geometric under which the water flows. At first, we supposed that the silhouette influence approaches zero; under this assumption, the modified equation collapsed to the ordinary groundwater flow equation. We proposed an analytical solution to the standard version of groundwater as a function of time, space and uncertainty factor α. Our proposed solution was in good agreement with experimental data. We presented a good approximation to the exponential integral. We obtained an asymptotic special solution to the modified equation by means of the Adomian decomposition and variational iteration methods.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

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