scholarly journals New Method for Calculating the Heating of the Conductor

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2769
Author(s):  
Voršič ◽  
Maruša ◽  
Pihler
Keyword(s):  
Heat Transfer ◽  
Tensile Strength ◽  
Steady State ◽  
Natural Convection ◽  
Simple Model ◽  
Solar Radiation ◽  
Balance Of Power ◽  
Stable Operation ◽  
The Core ◽  
Steel Core

The paper describes the core heating of ACSR (aluminum conductor steel—reinforced) conductor in stable operation under different environmental conditions. The calculations are greatly simplified in a steady state—we can calculate on a balance of power instead of a balance of energies. At a known surface, the temperature of the conductor due to solar radiation, natural convection, and joules heating as well as the temperature of the steel core were calculated, which is relevant for the tensile strength of the rope. Measurements of the surface of the conductor and the core rejected a simple model of heat transfer—it is also necessary to take into account empty air spaces between the wires of a rope. On the basis of measurements, a new model has given satisfactory compliance with the measured values.

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

scholarly journals Computational Performance of Disparate Lattice Boltzmann Scenarios under Unsteady Thermal Convection Flow and Heat Transfer Simulation

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 65
Author(s):  
Aditya Dewanto Hartono ◽  
Kyuro Sasaki ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Results ◽  
Convection And Heat Transfer ◽  
Steady State Condition ◽  
Physical Systems ◽  
Flow And Heat Transfer ◽  
Computational Performance

The present work highlights the capacity of disparate lattice Boltzmann strategies in simulating natural convection and heat transfer phenomena during the unsteady period of the flow. Within the framework of Bhatnagar-Gross-Krook collision operator, diverse lattice Boltzmann schemes emerged from two different embodiments of discrete Boltzmann expression and three distinct forcing models. Subsequently, computational performance of disparate lattice Boltzmann strategies was tested upon two different thermo-hydrodynamics configurations, namely the natural convection in a differentially-heated cavity and the Rayleigh-Bènard convection. For the purposes of exhibition and validation, the steady-state conditions of both physical systems were compared with the established numerical results from the classical computational techniques. Excellent agreements were observed for both thermo-hydrodynamics cases. Numerical results of both physical systems demonstrate the existence of considerable discrepancy in the computational characteristics of different lattice Boltzmann strategies during the unsteady period of the simulation. The corresponding disparity diminished gradually as the simulation proceeded towards a steady-state condition, where the computational profiles became almost equivalent. Variation in the discrete lattice Boltzmann expressions was identified as the primary factor that engenders the prevailed heterogeneity in the computational behaviour. Meanwhile, the contribution of distinct forcing models to the emergence of such diversity was found to be inconsequential. The findings of the present study contribute to the ventures to alleviate contemporary issues regarding proper selection of lattice Boltzmann schemes in modelling fluid flow and heat transfer phenomena.

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
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Shape Factor ◽  
Field Research ◽  
Circuit Model ◽  
The Finite Element Method ◽  
Heat Transfer Characteristics ◽  
Thermal Circuit ◽  
The Core ◽  
Conductor Temperature

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.

Natural Convection Inside a Bidisperse Porous Medium Enclosure

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Arunn Narasimhan ◽  
B. V. K. Reddy
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Phase ◽  
Darcy Number ◽  
The Core ◽  
Side Walls ◽  
Porous Blocks ◽  
Rayleigh Numbers

Bidisperse porous medium (BDPM) consists of a macroporous medium whose solid phase is replaced with a microporous medium. This study investigates using numerical simulations, steady natural convection inside a square BDPM enclosure made from uniformly spaced, disconnected square porous blocks that form the microporous medium. The side walls are subjected to differential heating, while the top and bottom ones are kept adiabatic. The bidispersion effect is generated by varying the number of blocks (N2), macropore volume fraction (ϕE), and internal Darcy number (DaI) for several enclosure Rayleigh numbers (Ra). Their effect on the BDPM heat transfer (Nu) is investigated. When Ra is fixed, the Nu increases with an increase in both DaI and DaE. At low Ra values, Nu is strongly affected by both DaI and ϕE. When N2 is fixed, at high Ra values, the porous blocks in the core region have negligible effect on the Nu. A correlation is proposed to evaluate the heat transfer from the BDPM enclosure, Nu, as a function of Raϕ, DaE, DaI, and N2. It predicts the numerical results of Nu within ±15% and ±9% in two successive ranges of modified Rayleigh number, RaϕDaE.

Transient Natural Convection Experiments in Shallow Enclosures

1982 ◽  
Vol 104 (3) ◽  
pp. 533-538 ◽  
Author(s):  
R. Yewell ◽  
D. Poulikakos ◽  
A. Bejan
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Theoretical Prediction ◽  
Thermal Stratification ◽  
Wave Motion ◽  
The Core ◽  
Transient Natural Convection ◽  
Aspect Ratios ◽  
Approach To Steady State ◽  
Rayleigh Numbers

This paper reports experimental observations on transient natural convection in enclosures at high Rayleigh numbers (1.28×109, 1.49×109) and low aspect ratios (0.0625, 0.112). The phenomenon consists of the establishment of thin intrusion layers along the horizontal adiabatic surfaces; in time, the intrusion layers exchange heat with the isothermal core of the cavity, leading to the thermal stratification of the core. The approach to steady state is gradual, contrary to the theoretical prediction of Brunt-Vaisala wave motion (Patterson and Imberger [6]). The measured durations of the observed transients agree very well with theoretical estimates.

Heat Transfer Enhancement in Ventilated Brake Disk Using Double Airfoil Vanes

2011 ◽  
Vol 3 (4) ◽  
Author(s):  
A. Nejat ◽  
M. Aslani ◽  
E. Mirzakhalili ◽  
R. Najian Asl
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Steady State ◽  
Simple Model ◽  
Transfer Enhancement ◽  
Brake Disk ◽  
Pumping Efficiency ◽  
Angular Velocities ◽  
The Heat Transfer Coefficient ◽  
Novel Design

The aim of this research is to enhance the heat transfer of ventilated brake disks using modified vanes. The investigated braking scenario is a hold braking deceleration during a downhill drive. A simple model for computing the steady state vane’s temperature is presented. The heat transfer coefficient (HTC) of the brake disk’s ventilation is estimated by means of a verified CFD computation. A novel design for the vanes is proposed using an airfoil profile to improve the air pumping efficiency increasing the flow velocity between vanes. For further improving the ventilating capacity, a secondary airfoil vane is introduced to the primary airfoil vane design. The computed results estimate 17% to 29% improvement in HTC number for new vane design at different disk’s angular velocities.

scholarly journals NUMERICAL STUDY FOR INTERRUPTED RECTANGULAR FINS IN A NATURAL CONVECTION FIELD

2019 ◽  
Vol 11 (2) ◽  
pp. 216-228
Author(s):  
Ass. Prof. Dr. Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Numerical Model ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins investigated numerically in a natural convection field, and with steady-state heat transfer. Numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins). The number of fins used on the surface are eight. In this study, the heat input that is  used as follow (20, 40, 60, 80, 100, and 120 watts). The study is focused on interrupted rectangular fins with different arrangement of fins. The results show that the addition of interruption fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate obtained as an equation.                                                         

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