Research on Numerical Simulation of Heliostat's Surface Wind Pressure

2012 ◽  
Vol 517 ◽  
pp. 809-816 ◽  
Author(s):  
Ying Ge Wang ◽  
Zheng Nong Li
Keyword(s):  
Numerical Simulation ◽  
Surface Wind ◽  
Three Dimensional ◽  
Wind Tunnel Test ◽  
Operating Conditions ◽  
Wind Pressure ◽  
Wind Resistance ◽  
Pressure Distributions ◽  
Complex Projects ◽  
Simulation Based

Heliostat is the major part of solar tower power station whose wind resistance is deemed significant in design. The CFD model of single heliostat under typical operating situation was founded by technology of numerical simulation based on standard k-ε model. This paper puts forward a mesh generation method applied to complex projects under different working conditions. The corresponding UDF program was framed & used to simulate proper wind field entry conditions. The wind pressure distributions variation rules at different wind direction & elevation angles got summarized. The drag coefficients, the lift coefficients, and the three-dimensional moment coefficients in wind power coordinate under different operating conditions were computed. The results agree well with experimental data though a little bigger error exists locally. Moreover, the flow field distribution hard to acquire in wind tunnel test was compensated to further explain origin of heliostats wind pressure distribution. The influencing factors and the variation rules discovered reveals that prediction by numerical simulation is practically satisfactory.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

Numerical Simulation Study of Coal Gangue Piles Influence on the Wind Pressure Distributions of Coal Reservoir Roofing

2011 ◽  
Vol 94-96 ◽  
pp. 535-538
Author(s):  
Zhi Xiang Yin ◽  
Cheng Jie Zhang
Keyword(s):  
Local Area ◽  
Coal Gangue ◽  
Wind Pressure ◽  
Leeward Side ◽  
Wind Resistance ◽  
Pressure Distributions ◽  
Coefficient Distribution ◽  
Average Wind ◽  
Fluent Software ◽  
Coal Reservoir

The influence of the wind coefficient distribution on coal reservoirs for coal gangue is very important to its wind-resistance design. Take a real coal reservoir in Ordos for example, the wind pressure is numerically simulated with the help of Fluent Software. Because of the coal gangue piples, the average wind coefficient absolute obviously reduced under most of the wind directions, but the local area on the surface and leeward side the average wind coefficient absolute will increase significantly under the certain wind directions. Anyhow, the coal gangue is important to the wind pressure distributions of the coal reservoir and can't ignore its effect in the actual engineering design and should be given more attention.

Numerical Simulation and Stereo PIV Test of Inner Flow in a Double Blades Pump

2011 ◽  
Author(s):  
Kai Wang ◽  
Houlin Liu ◽  
Shouqi Yuan ◽  
Minggao Tan ◽  
Yong Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Velocity Field ◽  
Cfd Simulation ◽  
Research Work ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Absolute Velocity ◽  
Operation Condition ◽  
Test Technique ◽  
Simulation Results

A double blades pump is widely used in sewage treatment industry, while at present the research on the internal flow characteristics of the double blades pump is very few. So, the CFD technology and the stereo PIV test technique are applied to study the inner flow in a double blades pump whose specific speed is 110.9. The commercial code FLUENT is used to simulate the inner flow in the double blades pump at 0.6Qd, 0.8Qd, 1.0Qd, 1.2Qd and 1.4Qd. The RNG k-ε turbulence model and SIMPLEC algorithm are used in FLUENT. According to the results of the three-dimensional steady numerical simulation, the distributions of velocity field in the impeller are obtained at the five different operating conditions. The analysis of the numerical simulation results shows that there is an obvious vortex in the impeller passage at off-design conditions. But the number, location and area of the vortex are different from each operation condition. In order to validate CFD simulation results, the stereo PIV is used to test the absolute velocity distribution in the double blades pump at Jiangsu University. The distributions of three-dimensional absolute velocity field at the above five different operating conditions are obtained by the PIV test, and the measured results are compared with the CFD simulation results. The comparison indicates that there are vortexes in impeller passages of the double blades pump under the five operating conditions. But as to the area of the vortex and the relative velocity values of the vortex core, there are some differences between the experiment results and the numerical simulation results. The research work can be applied to instruct the hydraulic design of double blades pumps.

Analysis of Stability of Mine Airflow

2014 ◽  
Vol 614 ◽  
pp. 91-96
Author(s):  
Chao Cui ◽  
Xian Ping Xie ◽  
Wen Gui Luo ◽  
Ting Jun Wang ◽  
Jian Gong Li ◽  
...  
Keyword(s):  
Membership Function ◽  
Flow Instability ◽  
Operating Conditions ◽  
Wind Pressure ◽  
Random Disturbance ◽  
Wind Resistance ◽  
Quantitative Analysis Method ◽  
Analysis Of Stability ◽  
Natural Wind ◽  
Mathematics Method

Firstly, the causes of mine air flow instability were analyzed in this paper, then the paper applied fuzzy mathematics method and got construction method of the membership function of airflow stability. Wind resistance of shaft and lane, natural wind pressure, operating conditions of fan and other random disturbance conditions are defined by membership function of relative stability degree of mine airflow. This paper provided a quantitative analysis method for the mine airflow stability.

Design and Research of Wind Tunnel Test for Deflectable Nose

2013 ◽  
Vol 423-426 ◽  
pp. 2063-2067
Author(s):  
Bo Zhang ◽  
Shu Shan Wang ◽  
Meng Yu Cao ◽  
Yu Xin Xu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flat Plate ◽  
Surface Pressure ◽  
Wind Tunnel Test ◽  
Cost Effective ◽  
Trajectory Control ◽  
Attack Angle ◽  
Rubber Tube ◽  
Pressure Distributions

A wind tunnel test is designed to study aerodynamic effects of one individual rocket with deflectable nose. The test measures pressure with U-bend tube which is cost effective. Using rubber tubes in different lengths to measure pressure distributions of a flat-plate, and calculating how rubber tube affects the measurement, in order to modify the measured surface pressure of the nose. The surface pressure varies on different points while yawing angle and attack angle changes, the changing regularity could provide data for following numerical simulation and trajectory control.

The Numerical Simulation of the Impact on the Hangzhou Bay Bridge Offshore Platform and the Sightseeing Tower

2012 ◽  
Vol 532-533 ◽  
pp. 352-356
Author(s):  
Hua Bai ◽  
Fang Liang Wang ◽  
Yu Li
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Surface Pressure ◽  
Wind Tunnel Test ◽  
Offshore Platform ◽  
Wind Pressure ◽  
Windward Side ◽  
Hangzhou Bay ◽  
Leeward Side ◽  
The Impact

In this paper, the distribution of surface wind pressure and wind speed of Hangzhou bay bridge, offshore platform and sightseeing tower is numerically simulated based on Fluent. Two turbulence models, standard k ε model and Realizable k ε model, are used. The influence of the wind pressure distribution of the offshore platform and sightseeing tower by Hangzhou bay bridge is also analyzed. And the detailed comparison between numerical simulation and wind tunnel test is given. Results show that the impact of Hangzhou bay bridge on platform and sightseeing tower occurs mainly with the angle of the wind less than 450. When the angle of the wind is more than 450, the impact is little. The upper of the sightseeing tower does not almost suffer the effect of other buildings. The surface pressure of the platform changes from 5% to 15% between under bridge and under non-bridge condition. The surface pressure of sightseeing tower changes from 0.05% to 3%. The influence on the platform by the bridge is significant but not significant on the sightseeing tower. The simulation results of the tower and mast structure given by both standard k ε model and Realizable k ε model find that the windward side is ideal; the crosswind side is the best; the leeward side is less than ideal. By contrast, the Realizable k ε model is a closer correlation with wind tunnel test than standard k ε model.

scholarly journals Three-dimensional inhomogeneous thermal fields of the “Photon-Amur 2.0” payload electronic board developed for nanosatellites

2021 ◽  
Vol 20 (2) ◽  
pp. 74-82
Author(s):  
D. V. Fomin ◽  
M. A. Barulinа ◽  
A. V. Golikov ◽  
D. O. Strukov ◽  
A. S. German ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Thermal Effect ◽  
Outer Space ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Control Board ◽  
Electronic Components ◽  
Thermal Fields ◽  
Electronic Board ◽  
High Orbit

The thermal fields of the Photon-Amur 2.0 payload electronic board developed for nanosatellites were studied. The Photon-Amur 2.0 payload consists of an electronic control board with a casing mounted in a nanosatellite and a remote panel with experimental photovoltaic converters. A modified heat balance method was used for numerical simulation of the thermal fields of the control board and the casing. The constructed model and the obtained results of the numerical simulation were verified by comparison with the thermal diagrams obtained for the Photon-Amur 2.0 electronic board under normal operating conditions. For modeling the outer space operating conditions, it was assumed that there is a vacuum outside and inside the Photon-Amur 2.0 casing, and the thermal effect is transmitted from the nanosatellite racks to the payload electronic board through the fastenings. The thermal effect is of a periodic nature with amplitude of 45 to +80○C and a period of 96 min, which approximately corresponds to the motion of a nanosatellite in a 575 km-high orbit. It was demonstrated that with such composition of the payload module, its casing can work as a passive thermoregulator of thermal fields on the electronic board of Photon-Amur 2.0. The simulation showed that the casing helps to keep the temperature on the control board in the interval of 15C to +85C, which is acceptable for the electronic components used on the payload control board.

EXPERIMENTAL AND NUMERICAL STUDY OF THE EFFECT OF A PIER ON SHIP TRAJECTORIES IN CURRENTS

2021 ◽  
Vol 156 (A1) ◽  
Author(s):  
W L Luo ◽  
C Guedes Soares ◽  
Z J Zou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Current Flow ◽  
Numerical Study ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Drift Motion ◽  
Ship Manoeuvring ◽  
Simulation Based ◽  
Experimental Findings

A study is presented of the effect of a pier on ship trajectories in currents. The current flow field around the pier is investigated. Experiments on ship manoeuvring and drift motion in the vicinity of a rectangular pier were carried out in a tank. Different current velocities and current angles were taken into account. The characteristics of the deviations of the ship trajectories from the initial course around the pier are investigated. Experimental findings indicate that the minimum required distance for safety navigation becomes larger with an increase of the current velocity. To obtain the details of continuous three-dimensional flow field around a pier, numerical simulation based on CFD calculations is conducted. The validity of the numerical simulation is demonstrated by comparison with experimental results.

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