Brownout Simulations of Model-Rotors In Ground Effect

In this work computational fluid dynamics is used to validate experimental results for a two-bladed small rotor In Ground Effect conditions. The paper focuses on the evaluation and prediction of the rotor outwash generated in ground effect. Time-averaged outflow velocities are compared with experimental results, and the simulated flow field is used for safety studies using the PAXman model and particle tracking methods. The aircraft weights have been studied, evaluating scaling factors to define how helicopter weight can affect the outflow forces and the particle paths. Results show how the wake generated by heavier helicopters can lead to stronger forces on ground personnel and push the particles farther away from the rotor.

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Efficiency prediction for storage chambers using computational fluid dynamics

Water Science & Technology ◽

10.2166/wst.1996.0202 ◽

1996 ◽

Vol 33 (9) ◽

pp. 163-170 ◽

Cited By ~ 4

Author(s):

Virginia R. Stovin ◽

Adrian J. Saul

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Shear Stress ◽

Particle Tracking ◽

Critical Value ◽

Complex Geometries ◽

Bed Shear Stress ◽

Breadth Ratio ◽

Computational Fluid Dynamics Cfd ◽

Simulated Flow

Research was undertaken in order to identify possible methodologies for the prediction of sedimentation in storage chambers based on computational fluid dynamics (CFD). The Fluent CFD software was used to establish a numerical model of the flow field, on which further analysis was undertaken. Sedimentation was estimated from the simulated flow fields by two different methods. The first approach used the simulation to predict the bed shear stress distribution, with deposition being assumed for areas where the bed shear stress fell below a critical value (τcd). The value of τcd had previously been determined in the laboratory. Efficiency was then calculated as a function of the proportion of the chamber bed for which deposition had been predicted. The second method used the particle tracking facility in Fluent and efficiency was calculated from the proportion of particles that remained within the chamber. The results from the two techniques for efficiency are compared to data collected in a laboratory chamber. Three further simulations were then undertaken in order to investigate the influence of length to breadth ratio on chamber performance. The methodology presented here could be applied to complex geometries and full scale installations.

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The Effect of Different Turbulence Models on the Emitter Discharge by Using Computational Fluid Dynamics

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.662.586 ◽

2013 ◽

Vol 662 ◽

pp. 586-590

Author(s):

Gang Lu ◽

Qing Song Yan ◽

Bai Ping Lu ◽

Shuai Xu ◽

Kang Li

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Field ◽

Turbulence Models ◽

Experimental Results ◽

Turbulent Model ◽

Simulation Results ◽

Rsm Model ◽

Dynamics Method ◽

Emitter Discharge

Four types of Super Typhoon drip emitter with trapezoidal channel were selected out for the investigation of the flow field of the channel, and the CFD (Computational Fluid Dynamics) method was applied to simulate the micro-field inside the channel. The simulation results showed that the emitter discharge of different turbulent model is 4%-14% bigger than that of the experimental results, the average discharge deviation of κ-ω and RSM model is 5, 4.5 respectively, but the solving efficiency of the κ-ω model is obviously higher than that of the RSM model.

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Assessment of the Flow Field in the HeartMate 3 Using Three-Dimensional Particle Tracking Velocimetry and Comparison to Computational Fluid Dynamics

ASAIO Journal ◽

10.1097/mat.0000000000000987 ◽

2020 ◽

Vol 66 (2) ◽

pp. 173-182 ◽

Cited By ~ 2

Author(s):

Bente Thamsen ◽

Utku Gülan ◽

Lena Wiegmann ◽

Christian Loosli ◽

Marianne Schmid Daners ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Field ◽

Particle Tracking ◽

Particle Tracking Velocimetry ◽

Three Dimensional

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Numerical investigations on effect of wear-ring clearance on performance of a submersible well pump

Advances in Mechanical Engineering ◽

10.1177/1687814017704155 ◽

2017 ◽

Vol 9 (7) ◽

pp. 168781401770415 ◽

Cited By ~ 3

Author(s):

Weidong Shi ◽

Xiongfa Gao ◽

Qihua Zhang ◽

Desheng Zhang ◽

Daoxing Ye

Keyword(s):

Fluid Dynamics ◽

Numerical Simulation ◽

Computational Fluid Dynamics ◽

Flow Field ◽

Reverse Flow ◽

Internal Flow ◽

Experimental Results ◽

Ring Size ◽

Numerical Investigations ◽

Calculation Results

A typical submersible well pump was investigated in this article. The whole flow field of submersible well pump was numerically simulated by computational fluid dynamics software. The influence of clearance of wear-rings on the external characteristic and internal flow field was analyzed through comparing the calculation results with experimental results. The result of the numerical simulation shows that changing clearance of front wear-ring has a greater impact on pump performances than changing clearance of back wear-ring, and the head and efficiency of pump decrease with the increase in the size of clearance. Especially when the size of clearance is larger than 0.5 mm, decreasing becomes more obvious. When the front and back wear-ring size of the clearance comes to 1.0 mm, the efficiency decreases from the highest point of 75.31% to 65.44% at rated flow, and the head of pump decreases about 3.5 m. When the size of clearance is 0.2 mm, reverse-flow will appear in the front shroud cavity of the impeller, and leakage from back wear-ring through the balance hole into the impeller, which has a little influence on the flow field of the impeller inlet.

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Field testing CFD-based predictions of storage chamber gross solids separation efficiency

Water Science & Technology ◽

10.2166/wst.1999.0467 ◽

1999 ◽

Vol 39 (9) ◽

pp. 161-168 ◽

Cited By ~ 8

Author(s):

Virginia R. Stovin ◽

Adrian J. Saul ◽

Andrew Drinkwater ◽

Ian Clifforde

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Settling Velocity ◽

Separation Efficiency ◽

Flow Patterns ◽

Total Efficiency ◽

Separation Performance ◽

Storage Chamber ◽

Solids Separation ◽

Simulated Flow

The use of computational fluid dynamics-based techniques for predicting the gross solids and finely suspended solids separation performance of structures within urban drainage systems is becoming well established. This paper compares the result of simulated flow patterns and gross solids separation predictions with field measurements made in a full size storage chamber. The gross solids retention efficiency was measured for six different storage chambers in the field and simulations of these chambers were undertaken using the Fluent computational fluid dynamics software. Differences between the observed and simulated flow patterns are discussed. The simulated flow fields were used to estimate chamber efficiency using particle tracking. Efficiency results are presented as efficiency cusps, with efficiency plotted as a function of settling velocity. The cusp represents a range of efficiency values, and approaches to the estimation of an overall efficiency value from these cusps are briefly discussed. Estimates of total efficiency based on the observed settling velocity distribution differed from the measured values by an average of ±17%. However, estimates of steady flow efficiency were consistently higher than the observed values. The simulated efficiencies agreed with the field observations in identifying the most efficient configuration.

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Construction Ventilation Scheme Optimization of Underground Main Powerhouse Based on CFD

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.368-370.619 ◽

2013 ◽

Vol 368-370 ◽

pp. 619-623

Author(s):

Zhen Liu ◽

Xiao Ling Wang ◽

Ai Li Zhang

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Field ◽

Air Flow ◽

Scheme Optimization ◽

Pressure Distributions ◽

Air Volume ◽

Computational Fluid Dynamics Cfd ◽

Traditional Construction ◽

Ventilation Scheme

For the purpose of avoiding the deficiency of the traditional construction ventilation, the ventilation of the underground main powerhouse is simulated by the computational fluid dynamics (CFD) to optimize ventilation parameters. A 3D unsteady RNG k-ε model is performed for construction ventilation in the underground main powerhouse. The air-flow field and CO diffusion in the main powerhouse are simulated and analyzed. The two construction ventilation schemes are modelled for the main powerhouse. The optimized ventilation scheme is obtained by comparing the air volume and pressure distributions of the different ventilation schemes.

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Effect of Doppler flow meter position on discharge measurement in surcharged manholes

Water Science & Technology ◽

10.2166/wst.2017.563 ◽

2017 ◽

Vol 77 (3) ◽

pp. 647-654 ◽

Cited By ~ 1

Author(s):

Haoming Yang ◽

David Z. Zhu ◽

Yanchen Liu

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Field ◽

Flow Regimes ◽

Flow Meter ◽

Flow Meters ◽

Flow Discharge ◽

Doppler Flow ◽

Sewer Systems ◽

Computational Fluid Dynamics Cfd

Abstract Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.

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Numerical Investigation of Thermal Flow Field of Air-Cooled Condensers for Yongshou Plant

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.248.391 ◽

2012 ◽

Vol 248 ◽

pp. 391-394

Author(s):

Wen Zhou Yan ◽

Wan Li Zhao ◽

Qiu Yan Li

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Speed ◽

Power Plant ◽

Flow Field ◽

Wind Direction ◽

Rotational Speed ◽

Power Plants ◽

Thermal Flow ◽

Air Cooled Condensers

By using the computational fluid dynamics code, FLUENT, Numerically simulation is investigated for Youngshou power plant. Under the constant ambient temperature, the effects of different wind speed and wind direction on the thermal flow field are qualitatively considered. It was found that when considering about the existing and normally operating power plants, the thermal flow field is more sensitive to wind direction and wind speed. Based on the above results, three improved measures such as: increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively improving the thermal flow field, and enhanced the heat dispersal of ACC.

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CFD Leakage Predictions of Unworn and Worn Labyrinth Seals With and Without Tooth Axial Offset

Volume 5B: Heat Transfer ◽

10.1115/gt2017-63163 ◽

2017 ◽

Author(s):

Hasham H. Chougule ◽

Alexander Mirzamoghadam

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Numerical Modeling ◽

Steady State ◽

Flow Field ◽

Labyrinth Seals ◽

Small Clearance ◽

Total Leakage ◽

Computational Fluid Dynamics Cfd ◽

Flow Deflection

The objective of this study is to develop a Computational Fluid Dynamics (CFD) based methodology for analyzing and predicting leakage of worn or rub-intended labyrinth seals during operation. The simulations include intended tooth axial offset and numerical modeling of the flow field. The purpose is to predict total leakage through the seal when an axial tooth offset is provided after the intended/unintended rub. Results indicate that as expected, the leakage for the in-line worn land case (i.e. tooth under rub) is higher compared to unworn. Furthermore, the intended rotor/teeth forward axial offset/shift with respect to the rubbed land reduces the seal leakage. The overall leakage of a rubbed seal with axial tooth offset is observed to be considerably reduced, and it can become even less than a small clearance seal designed not to rub. The reduced leakage during steady state is due to a targeted smaller running gap because of tooth offset under the intended/worn land groove shape, higher blockages, higher turbulence and flow deflection as compared to worn seal model without axial tooth offset.

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