Study on the Steady State Thermal Circuit Model of 10kV Three-Core Cable Based on the Shape Factor Method

2014 ◽  
Vol 1008-1009 ◽  
pp. 593-597
Author(s):  
Wen Xiang Li ◽  
Rui Bo Su ◽  
Gang Liu ◽  
Peng Wang ◽  
Yi Xuan Chen

The core of the 10kV three-core cable is in the shape of a trefoil. Not all the radial direction of the actual heat transfer characteristics are the same. The finite element method serve as the three core cable temperature field research method in this text, in order to analyze the internal temperature distribution of three core cable, establish a steady state thermal circuit model in accordance with the characteristics of heat transfer from the cable conductor to the surface in the three-core cable , give the calculation of conductor temperature algorithm, and calculate the various parameters in the model.

2014 ◽  
Vol 1008-1009 ◽  
pp. 588-592
Author(s):  
Wen Xiang Li ◽  
Rui Bo Su ◽  
Gang Liu ◽  
Peng Wang ◽  
Zhen Ning Pan

The paper focus on the influence of the deviation of material thermal resistance coefficient on the conductor temperature calculations, based on the three-core cable thermal circuit model. Meanwhile we also design a temperature rise test of the 10kv three-core cable in step current, measuring the temperature of the cable structure in different steady state. Then we calculate the thermal resistance of the cable body and the thermal resistance of the layer material , find the change law of the thermal resistance with the temperature and analyses the effect of the dynamic characteristic of the material thermal resistance on the conductor temperature calculations in the three-core cable thermal circuit model.


Author(s):  
Shiyan Sun ◽  
Youjie Zhang ◽  
Yanhua Zheng ◽  
Xiang Fang ◽  
Xiaoyong Yang

During the operation of the High Temperature Gas-cooled Reactor (HTGR), the hot-spot temperature in the reactor core must be lower than the maximum permissible temperature of the fuel elements and the materials of construction, so that the reactor kept safe. However, no fixed temperature-measuring devices can be set in a pebble-bed core. A special spherical temperature-measuring device is adopted to make sure it brings as small impact to the reactor operation as possible. There are several metal wires with different melting points inside. The graphite thermometric balls will be put onto the top of HTR-10 reactor core, and they record and reflect the highest temperature in different positions in the core when flowing in the pebble bed. Before the reactor core temperature-measuring experiment of HTR-10, we must study the heat transfer characteristics of the graphite thermometric sphere to find out the relationship of the melting conditions and the temperature in the reactor core. A 3-D model of the graphite thermometric ball is established, and CFD method is adopted to research and figure out the thermal equilibrium time and temperature difference between the metal wires in the ball and the hot fluid outside the balls. Multiple situations are simulated, and the heat transfer process of the thermometric sphere is comprehensively studied. The heat convection is certified the most important aspect. Thermal equilibrium can be achieved within 19 minutes, far shorter than the period while the spheres flowing through the core. The simulation results can also applied to derive the thermal fluid temperature backward.


Author(s):  
Mengwei Zhang ◽  
Bin Zhang ◽  
Jianqiang Shan

Nuclear reactor severe accidents can lead to the release of a large amount of radioactive material and cause immense disaster to the environment. Since the Fukushima nuclear accident in Japan, the severe accident research has drawn worldwide attention. Based on the one-dimensional heat conduction model, a DEBRIS-HT program for analyzing the heat transfer characteristics of a debris bed after a severe accident of a sodium-cooled fast reactor was developed. The basic idea of the DEBRIS-HT program is to simplify the complex energy transfer process in the debris bed to a simple one-dimensional heat transfer problem by solving the equivalent thermal conductivity in different situations. In this paper, the DEBRIS-HT program code is prepared by using the existing model and compared with the experimental results. The results show that the DEBRIS-HT program can correctly predict the heat transfer process in the fragment bed. In addition, the heat transfer characteristics analysis program is also used to model the core catcher of the China fast reactor. Firstly, the dryout heat flux when all of molten core dropped on the core catcher was calculated, which was compared with the result of Lipinski’s zero dimensional model, and the error between two values is only 11.2%. Then, the temperature distribution was calculated with the heat power of 15MW.


2021 ◽  
Vol 2133 (1) ◽  
pp. 012034
Author(s):  
Jianfeng En ◽  
Ziyao Ma ◽  
Siran Jia ◽  
Jie Mu ◽  
Zhenbang Gao

Abstract In this paper, a rectangular flow runner is used as the research object to study the influence of adding a spoiler on the wall of the flow runner on its heat transfer characteristics and flow characteristics. Using the finite element method to analyse the influence of different spoiler’s structures and parameters of the spoilers on the heat transfer characteristics and flow characteristics of the flow runner, the study found that: by the comparison of the smooth flow runner and the rectangular spoiler flow runner, the comprehensive heat exchange effect of the spoiler runner is the best when the arc is arranged in the flow runner, and the accumulation effect of impurities in the runner is the slowest.


Author(s):  
Agarwal A ◽  
◽  
Molwane O.B ◽  
Letsatsi M.T ◽  
◽  
...  

During braking process, the kinetic energy of vehicle reduces and gets converted in thermal energy due to friction between disk and brake pads. The disk brake is used to retard the motion of vehicle by pressing brake pads against disk rotors. The frequent braking or panic braking results in overheating of brake disks which may result in brake fade. It is therefore essential to test newer materials which are more effective and possess better heat transfer characteristics than conventional cast iron material. The current research investigates the application of Al MMC material for ATV disk brake using experimental and numerical techniques. The numerical analysis is conducted on both conventional cast iron and Al MMC disk brake under steady state conditions and dynamic conditions. The dynamic condition testing involved testing of disk brake with externally flowing air at 2.5m/s and 5m/s using techniques of Computational Fluid Dynamics (CFD). The CAD model of ATV disk brake is developed in Creo design software and CFD analysis is conducted using ANSYS CFX. The turbulence model used for analysis is RNG k-epsilon. The temperature and heat flux are determined for disk brake under steady state and dynamic conditions. The results have shown that disk brake made from Al MMC possess better heat transfer characteristics as compared to conventional cast iron and cooling time also reduces with increase in external air speed.


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