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.

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 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.

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.

Simulation and Identification of Nonstationary Heat Transfer in a Nonuniform Friction Contact

1993 ◽  
Vol 115 (2) ◽  
pp. 299-306 ◽  
Author(s):  
O. Bogatin ◽  
I. Chersky ◽  
N. Starostin
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Three Dimensional ◽  
Unit Element ◽  
Separation Coefficient ◽  
Friction Contact ◽  
Nonstationary Heat Transfer ◽  
Thermal Fields ◽  
Simulation Results ◽  
Marching Method

The results of numerical simulation of nonstationary thermal fields in cylindrical friction junctions are presented. On the basis of the marching method, a numerical algorithm which imposes no restrictions on the value of heat flow separation coefficient is constructed. Simulation results are given for different bearing designs both for the two and three-dimensional cases. Using the developed algorithm as a base, a method allowing for reconstruction of heat release and, hence, friction moment values from temperature measurements in the stationary unit element is suggested. Reliability of the results is proved by experiments.

Numerical Simulation of Turbulent Thermal Fluid in Tee Water Duct Cooled Nuclear Reactor

2015 ◽  
Vol 789-790 ◽  
pp. 484-488 ◽  
Author(s):  
Fethi Saidi ◽  
Mohammed Aounallah ◽  
Mustapha Belkadi ◽  
Lahouari Adjlout ◽  
Omar Imine
Keyword(s):  
Numerical Simulation ◽  
Nuclear Reactor ◽  
Three Dimensional ◽  
Good Prediction ◽  
Wall Function ◽  
Reversed Flow ◽  
Ansys Fluent ◽  
Thermal Mixing ◽  
Thermal Fields ◽  
Buoyancy Forces

The turbulent and thermal mixing in a vertically oriented T-junction is investigated numerically using ANSYS FLUENT software. By taking account the buoyancy forces, a steady state three-dimensional turbulent flow is considered with a Reynolds number of 0.4×105 at the cold inlet and 3.3×105 at the hot entrance. The k-ε standard model with standard wall function is chosen to provide closure for the Reynolds stress tensor. The numerical results presented in the form of velocity vectors field and contours of temperature distribution gave a good prediction of the dynamic and the thermal fields namely in the mixing region where a reversed flow is captured.

Experimental and Numerical Investigation of the Performance Impact of a Heavily Off-Design Inlet Swirl Angle in a Steam Turbine Stage

2017 ◽  
Author(s):  
Berardo Paradiso ◽  
Giacomo Gatti ◽  
Alessandro Mora ◽  
Vincenzo Dossena ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Turbine Stage ◽  
Test Rig ◽  
Speed Test ◽  
Performance Reduction ◽  
Inlet Conditions

The aim of this work is to provide an insight into the performance reduction of a 1.5 axial steam turbine stage working under extreme incidence conditions at the inlet. In particular, the main object of the study is the propagation of the loss cores across the blade rows, so as to assess how such operating conditions affect the full machine. Experimental data have been used to validate an unsteady three-dimensional numerical simulation, which provided the tools to investigate the flowfield in detail. To do so, the 1.5 turbine stage installed in the Low Speed Test Rig at Politecnico di Milano has been tested with design and off-design inlet conditions by modifying the IGV orientation. The inter-stage flowfield was investigated by traversing pressure probes in three different axial planes, downstream of each blade row. The numerical simulation has been carried out at University of Florence. The experimental data from probes traversing was used as boundary conditions so as to match as closely as possible the actual operative parameters of the stage. Data from flange-to-flange measurements on the test rig were also used to compare the stage efficiency. After the successful validation of the numerical results, the loss cores propagation study itself was carried out. Using CFD results, the unsteady nature of the separation occurring on the first stator in off-design condition is investigated. Subsequently, a detailed analysis of the propagation of the loss cores is presented, including loss coefficients calculation and entropy trends along the machines axial coordinate. The main outcome is that at the machine exit the loss structures appear to be mainly mixed out and, therefore, subsequent stages would operate under conditions not far from the nominal ones.

Study on Numerical Simulation and Performance Test of Tubular Pumping System

2013 ◽  
Author(s):  
Yan Jin ◽  
Chao Liu ◽  
Li Cheng
Keyword(s):  
Numerical Simulation ◽  
Optimization Design ◽  
Performance Test ◽  
High Efficiency ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Rotating Speed ◽  
Pumping System

Research on three-dimensional flow field in a tubular pumping system using numerical simulation based on the Reynolds time-averaged Navier-Stokes equations and the RNG k–ε turbulent model. By using this method, the performance of pumping system such as head, shaft power and efficiency are predicted based on the calculation of different operating conditions in the discharge range from 20L/s to 35L/s at the same rotating speed. For verifying the accuracy and reliability of the calculation results, a tubular pumping system bedstand is designed for the permarmance test. The comparison of simulation results and the experiment data shown that the calculation performances close agreement with the experiment results in the high efficiency area, but in the condition of large discharge and low discharge, deviations were existed between the two results. Combining with the results of numerical simulation and experiment, which can provide more evidences for the hydraulic performances prediction and optimization design of pumping system.

The Research on the Effects of the Multilayer Gauze Stage with Different Layers

2011 ◽  
Vol 230-232 ◽  
pp. 415-419
Author(s):  
Zhong Yi Wang ◽  
Jia Han ◽  
Tao Sun ◽  
Nan Ye
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Periodic Boundary ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Resistance Characteristic ◽  
Two Dimensional ◽  
Characteristic Curves ◽  
Numerical Simulation Result ◽  
The Relationship

The mesh of the multilayer gauze stage was simplified from the crossing arrangement to the unilateral arrangement, and the simplification from three-dimensional to the two-dimensional came true. The calculation capacity was effectively controlled by means of the periodic boundary. The numerical simulation of the multilayer gauze stage with different layers has been done. After the several calculation with different operating conditions, the resistance characteristic curves of the corresponding models was gave out. The relationship between the layers of the multilayer gauze stage and the resistance characteristic has been worked out. The experiments on resistance specialty of the multilayer gauze stage have been done on the special wind-tunnel. The experiment result was compared with the numerical simulation result, in order to provide the effective information for the further research.

scholarly journals Plasma vortex reactor for production of heat energy and hydrogen

2018 ◽  
Vol 209 ◽  
pp. 00009
Author(s):  
Anatolii Klimov ◽  
Svetlana Kurushina ◽  
Nonna Molevich ◽  
Denis Porfiriev ◽  
Igor Zaversinskii
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Qualitative Agreement ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Heat Energy ◽  
Experimental Conditions ◽  
Thermal Fields ◽  
Set Up ◽  
Vortex Reactor

Numerical simulation of the turbulent three-dimensional swirling flow structure in plasma vortex reactor is conducted. Flow and set up parameters correspond to the experimental conditions. Flow velocity and thermal fields have been obtained. A qualitative agreement between the results of the calculations and the experimental data for pure argon has been shown.

Research on Improving the Dynamic Performance of Centrifugal Pumps With Twisted Gap Drainage Blades

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Zheng-Chuan Zhang ◽  
Hong-Xun Chen ◽  
Zheng Ma ◽  
Jian-Wu He ◽  
Hui Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Hydraulic Performance ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Centrifugal Pumps ◽  
Practical Applications

Through numerical simulation and experiments analysis, it is indicated that the hydraulic and anticavitation performance of a centrifugal pump with twisted gap drainage blades based on flow control theory can be significantly improved under certain operating conditions. In order to introduce the technology of gap drainage to practical applications, we put forward the parameter formulas of the twisted gap drainage blade to design three-dimensional new type blade, which are also proved to be effective for enhancing the dynamic characteristics of the centrifugal pump. Furthermore, a practical centrifugal pump is redesigned to be a twisted gap drainage impeller with the same structure size as the original impeller, and the nonlinear hybrid Reynolds-averaged Navier–Stokes (RANS)/large eddy simulation (LES) method is employed to simulate the hydraulic dynamic characteristics. Numerical simulation results show that the hydraulic performance and dynamic characteristics of the redesigned impeller centrifugal pump are significantly enhanced. In experiments, the twisted gap drainage blades structure not only remarkably improves the hydraulic performance and the pressure pulsation characteristics of the centrifugal pump but also reduces the vibration intensity.

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