Experimental Measurements and Theoretical Predictions of the Thermohydraulic Performance of Clean Rooms for the Semi-Conductor Industry

1996 ◽  
Vol 210 (1) ◽  
pp. 9-18 ◽  
Author(s):  
G L Quarini ◽  
Y C Chang
Keyword(s):  
Food Processing ◽  
Semiconductor Manufacturing ◽  
Ventilation System ◽  
Experimental Measurements ◽  
Clean Room ◽  
Mean Flow ◽  
Numerical Predictions ◽  
Theoretical Predictions ◽  
Computational Fluid Dynamics Cfd ◽  
Good Agreement

There is a need to engineer working areas where air-borne pollution is below specified limits. This need arises from activities as diverse as food processing, semi-conductor manufacture and surgery. In this paper, detailed experimental measurements of flows in a semiconductor manufacturing room are reported. Computational fluid dynamics (CFD) has been used to study the flows within the room. Good agreement was found between the measured and predicted mean flow velocity distributions. Both the experimental measurements and the numerical predictions suggest that the ventilation system used in this room, which is of a common industrial design, does not produce ideal clean room conditions.

Turbulent Flow Around a Bluff Rectangular Plate. Part II: Numerical Predictions

1991 ◽  
Vol 113 (1) ◽  
pp. 60-67 ◽  
Author(s):  
N. Djilali ◽  
I. S. Gartshore ◽  
M. Salcudean
Keyword(s):  
Rectangular Plate ◽  
Marked Improvement ◽  
Separation Bubble ◽  
Reattachment Length ◽  
Mean Flow ◽  
Discretization Methods ◽  
Streamline Curvature ◽  
Pressure Distributions ◽  
Numerical Predictions ◽  
Good Agreement

This paper presents calculations of the time-averaged separated-reattaching flow around a bluff rectangular plate, using a finite difference procedure and the k-ε turbulence model. Two discretization methods are used: the hybrid differencing scheme, and the bounded skew hybrid differencing scheme. The latter, although superior to the former for all grid distributions, results in a reattachment length about 30 percent shorter than the measured value. When a modification which takes into account streamline curvature is incorporated into the k-ε model, a marked improvement in the predictions is obtained. A reattachment length of 4.3 plate thicknesses (D), compared to an experimental value of 4.7D, is obtained, and the predicted mean flow field, turbulent kinetic energy and pressure distributions within the separation bubble are found to be in good agreement with experiments.

Model Testing and CFD Analysis of 2D Profiles Towards Offshore Applications

2013 ◽  
Author(s):  
Lucas do Vale Machado ◽  
Antonio Carlos Fernandes ◽  
Gustavo César Rachid Bodstein
Keyword(s):  
Experimental Data ◽  
Experimental Measurements ◽  
Cfd Analysis ◽  
Two Dimensional ◽  
Reference Simulation ◽  
Sst Turbulence Model ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Naca 0015 ◽  
Good Agreement

In this paper we present numerical and experimental work motivated by the study of a rudder profile with significant levels of lift that provides better performance for the maneuvering and stabilization of a ship. This is the so-called Schilling profile. The analysis of the two-dimensional subsonic steady flow over four profiles was carried out using computational fluid dynamics (CFD) tools with a κ-ω SST turbulence model. We consider three Schilling profiles with different thicknesses and the classical NACA 0015 profile, taken as a reference. Simulation results were compared to our experimental measurements at various angles of attack and two orders of magnitude of the Reynolds number, 5.45 × 104 and 1.09 × 105. The numerical results show general good agreement with experimental data and highlight the distinct behavior of Schilling profile.

A Study of Diffuser/Rotor Interaction in a Centrifugal Compressor

1981 ◽  
Vol 23 (3) ◽  
pp. 149-156 ◽  
Author(s):  
E. H. Fisher ◽  
M. Inoue
Keyword(s):  
Centrifugal Compressor ◽  
Lift Coefficient ◽  
Singularity Theory ◽  
Mean Flow ◽  
Absolute Flow ◽  
Impeller Outlet ◽  
Theoretical Predictions ◽  
Flow Round ◽  
Stagger Angle ◽  
Good Agreement

Experimental flow data recorded on a low speed centrifugal compressor rig are compared with theoretical predictions of the diffuser field. Results for four diffuser geometries are presented covering variation of the blade number, stagger angle, and radial separation of the rotor and diffuser. The theoretical predictions are based on an extension of the Martensen surface singularity theory. The diffuser is found to play a major role in establishing the circumferential variation in the mean flow at impeller outlet. Large pitch wise variations are observed, which may be explained by consideration of the flow round the leading edges of the diffuser blades. Experiments and potential flow theory show good agreement, except for cases where the diffuser shows signs of separation. These are clearly identified from the theoretical predictions by Carter's lift coefficient criterion. Although the absolute flow at rotor outlet is markedly time-dependent owing to the passage of the rotor, it would appear that the averaged flow conditions may be predicted by the steady-state singularity program. Unstalled diffuser flows are accurately predicted and stalled flows, which are generally to be avoided, may be anticipated from the lift coefficient criterion. The designer thus has the option of reducing pitchwise velocity and pressure variations at rotor outlet to acceptable amplitudes.

Stiffness and Bond Strength of Rubber-Filled Hinges

1993 ◽  
Vol 66 (5) ◽  
pp. 733-741 ◽  
Author(s):  
A. N. Gent ◽  
Y-W. Chang
Keyword(s):  
Finite Element Analysis ◽  
Bond Strength ◽  
Direct Analysis ◽  
Test Method ◽  
Bond Rupture ◽  
Experimental Measurements ◽  
Element Analysis ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Good Agreement

Abstract The stiffness of rubber-filled hinges for small rotations of the hinge plates has been determined by finite element analysis (FEA). The rubber is assumed to be linearly elastic and virtually incompressible, and the hinge is assumed to be long enough for the rubber to be in a state of plane strain, i.e., prevented from any displacement parallel to the hinge. Results have been obtained for hinges of a wide range of unstrained angle, ranging from 5° up to 360°. The calculated stiffnesses for long hinges vary by over four orders of magnitude over this range. For small angles, an approximate solution has been obtained by direct analysis—it is in good agreement with the FEA solution for hinge angles up to about 40°. Experimental measurements on several rubber-filled hinges are also reported. The measured rotational stiffnesses are in satisfactory agreement with theoretical predictions. Because a rubber-filled hinge constitutes a possible test method for bond strength, conditions are derived for bond rupture as a hinge is strained open.

An Experimental and Theoretical Study of Transitional Turbulent Pulsatile Flow in a Channel

1976 ◽  
Vol 43 (4) ◽  
pp. 559-563 ◽  
Author(s):  
L. C. Thomas ◽  
J. Min
Keyword(s):  
Pulsatile Flow ◽  
Time Scale ◽  
Theoretical Study ◽  
Experimental Measurements ◽  
Surface Renewal ◽  
Theoretical Predictions ◽  
Good Agreement

Experimental measurements of the time scale τ(t) of the burst phenomenon are reported for laminar-transitional turbulent, fully developed, pulsatile flow in a channel. Theoretical predictions for τ(t) which are developed on the basis of a quasi-steady surface renewal formulation are shown to be in good agreement with the data.

Numerical Flow Prediction in Inlet Pipe of Vertical Inline Pump

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Christopher Stephen ◽  
Shouqi Yuan ◽  
Ji Pei ◽  
Xing Cheng G
Keyword(s):  
Stokes Equations ◽  
Reverse Flow ◽  
Pressure Coefficient ◽  
Navier Stokes ◽  
Mean Flow ◽  
Inlet Pipe ◽  
Navier Stokes Equations ◽  
Computational Fluid Dynamics Cfd ◽  
The Mean ◽  
Good Agreement

For a pump, the inlet condition of flow determines the outlet conditions of fluid (i.e., energy). As a rule to minimize the losses at the entry of pump, the bends should be avoided as one of the methods. But for the case of vertical inline pump, it is unavoidable in order to save the space for installation. For the purpose of investigation in inlet pipe of vertical inline pump, the unsteady Reynolds-averaged Navier–Stokes equations are solved using the computational fluid dynamics (CFD) code. The results have been shown that there is a good agreement between the performance characteristics obtained from the simulation and experiments. The velocity coefficient from the simulation along the inlet pipe sections is well matched with the theoretical values and found to have variation near the exit of inlet pipe. The pressure and velocity coefficients studies depict the flow physics at each section along with the study of helicity at the exit of inlet pipe to determine the recirculation effects. It is observed that the vortices associated with the motion of the particles are moved toward the surfaces and are more intense than the mean flow. The trends of pressure coefficient at the exit of inlet pipe were addressed with reference to the various flow rates for eight set of radial lines. Hence, this work concludes that for inlet pipe, the generation of circulation was due to the stream path and the reverse flow from the impeller and was reconfirmed with the literature.

Numerical Predictions for the Flow Induced by an Enclosed Rotating Disc

1988 ◽  
Author(s):  
John W. Chew ◽  
Craig M. Vaughan
Keyword(s):  
Experimental Data ◽  
Reasonable Agreement ◽  
Mixing Length ◽  
Mean Flow ◽  
Rotating Disc ◽  
Numerical Predictions ◽  
Stationary Disc ◽  
The Mean ◽  
Radial Outflow ◽  
Good Agreement

Finite difference solutions are presented for turbulent flow in the cavity formed between a rotating and a stationary disc, with and without a net radial outflow of fluid. The mean flow is assumed steady and axisymmetric and a mixing length model of turbulence is used. Grid dependency of the solutions is shown to be acceptably small and results are compared with other workers’ experimental data. Theoretical and measured disc moment coefficients are in good agreement, while theoretical and measured velocities are in reasonable agreement. It is concluded that the mixing-length model is sufficiently accurate for many engineering calculations of boundary layer dominated flows in rotating disc systems.

Hydroelastic Responses of a Flexible Hydrofoil in Turbulent, Cavitating Flow

2010 ◽  
Author(s):  
Antoine Ducoin ◽  
Yin Lu Young ◽  
Jean-Franc¸ois Sigrist
Keyword(s):  
Degrees Of Freedom ◽  
Experimental Studies ◽  
Cavitating Flow ◽  
Experimental Measurements ◽  
Naval Academy ◽  
Loosely Coupled ◽  
Numerical Predictions ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag ◽  
Twisting Deformation

The objective of this work is to develop and validate a robust method to simulate the hydroelastic responses of flexible hydrofoil in turbulent, cavitating flow. A two degrees-of-freedom (2-DOF) model is used to simulate the plunging and pitching motion at the foil tip due to bending and twisting deformation of a 3-D cantilevered hydrofoil. The 2-DOF model is loosely coupled with the commercial computational fluid dynamics (CFD) solver STAR-CCM+ to efficiently simulate the fluid-structure interaction (FSI) responses of a cantilevered, rectangular hydrofoil. The numerical predictions are compared with experimental measurements for cases with and without cavitation. The experimental studies were conducted in the cavitation tunnel at the French Naval Academy (IRENav), France. Only quasi-steady cases with Reynolds number (Re) of 750,000 are shown in this paper. In general, the numerical results agree well with the experimental measurements and observations. The results show that elastic deformation of the POM polyacetate (flexible) hydrofoil lead to increases in the angle of attack, which resulted in higher lift and drag coefficients, lower lift to drag ratio, and longer cavities compared to the stainless steel (rigid) hydrofoil. Whereas only stable cavitation cases are considered in this paper, significant interaction effects were observed during experiments for cases with unstable cavitation due to interations between the foil natural frequencies and the cavity shedding frequencies. Transient analysis of the FSI responses of 3-D elastic hydrofoils in turbulent, cavitating flow is currently under work.

“Bigfoot” DVA Semi-Submersible Model Tests and Comparison With Numerical Predictions

2015 ◽  
Author(s):  
Stergios Liapis ◽  
Yile Li ◽  
Haining Lu ◽  
Tao Peng
Keyword(s):  
Model Tests ◽  
Attractive Alternative ◽  
Force Measurements ◽  
Numerical Predictions ◽  
Order Of Magnitude ◽  
Drilling Operations ◽  
Computational Fluid Dynamics Cfd ◽  
Production Host ◽  
Motion Characteristics ◽  
Good Agreement

The Bigfoot direct vertical access (DVA) semisubmersible is a novel floating drilling and production host that provides an attractive alternative to the spar. This concept utilizes heave plates (big feet) that improve the motion characteristics of a semisubmersible in all mild environments (S.E. Asia, W. Africa and Brazil). Bigfoot offers direct-vertical access (DVA) which is often a project requirement. This floater works in all water depths, in particular ultra-deepwater (5000+ ft) where a tension leg platform (TLP) is not an option, supports top tensioned risers and enables drilling and workover operations. The Bigfoot has several advantages over a spar. These include: 1) Quayside topsides integration. This eliminates offshore topsides integration, a significant issue for all spar projects in terms of cost, safety and schedule. 2) A more open deck layout compared to a spar, 3) No fabrication location restrictions as it can be built by many yards worldwide potentially offering local content to a project. Model tests were undertaken at the Shanghai Jiao Tong University (SJTU) Offshore Basin to assess the dynamic response of the Bigfoot in waves, swell, wind and current. Five mild (non-Gulf of Mexico) environments were considered. In all cases, the floater motions are an order of magnitude smaller than those of a conventional semisubmersible for similar deck payload thus enabling drilling operations and top-tensioned production risers. In a parallel effort, a COSMOS numerical model of the Bigfoot was developed for coupled motion analysis. The experimental results and the COSMOS numerical predictions are in close agreement. In addition to measuring global motions, two heave plates were instrumented with load cells to measure forces and moments. The force measurements from the model tests are in good agreement with numerical predictions using computational fluid dynamics (CFD).

Numerical simulations and experimental measurements of the flow in a multi-tube heat exchanger

2005 ◽  
Vol 219 (4) ◽  
pp. 319-326 ◽  
Author(s):  
J. P. Hughes ◽  
G. H. Shaw ◽  
G. S. Tucker ◽  
P. W. James ◽  
T. E. R. Jones
Keyword(s):  
Heat Exchanger ◽  
Numerical Simulations ◽  
Isothermal Flow ◽  
Experimental Measurements ◽  
Shell Side ◽  
Tubular Heat Exchanger ◽  
Tube Heat Exchanger ◽  
Numerical Predictions ◽  
Side Flow ◽  
Good Agreement

This paper describes numerical simulations and experimental measurements of isothermal and non-isothermal flow of non-Newtonian fluids in the shell side of a multi-tube tubular heat exchanger. Some results for the turbulent isothermal flow of water are also presented. A single pass of a commercially available Tetra Spiraflo 7x16MT multi-tube heat exchanger has been instrumented to provide pressure drop and temperature data. Numerical predictions obtained with commercial software are generally in good agreement with measurements. The simulations are then used to determine more detailed features of the shell-side flow in this type of multi-tube heat exchanger. The work forms part of a project investigating the use of multi-tube heat exchangers in heat recovery mode for medium viscosity food products.

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