scholarly journals Experimental investigations on an axial grooved cryogenic heat pipe

2012 ◽  
Vol 16 (1) ◽  
pp. 133-138 ◽  
Author(s):  
Kumar Senthil ◽  
Kumar Senthil
Keyword(s):  
Steady State ◽  
Heat Pipe ◽  
Liquid Nitrogen ◽  
Experimental Investigations ◽  
Equivalent Diameter ◽  
Heat Loads ◽  
Steady State Performance

This paper deals with development and studies of a trapezoidal axial grooved nitrogen heat pipe. A special liquid nitrogen cryostat has been designed and developed for evaluating the performance of heat pipe where the condenser portion is connected to the cold sink externally. Experiments have been performed on the heat pipe as well as on an equivalent diameter copper rod at different heat loads. The steady state performance of the heat pipe is compared with that of copper rod.

Quasi-steady-state performance of a heat pipe subjected to transient acceleration loadings

10.2514/3.895 ◽  
1997 ◽  
Vol 11 ◽  
pp. 306-309 ◽  
Author(s):  
Edwin H. Olmstead ◽  
Edward S. Taylor ◽  
Meng Wang ◽  
Parviz Moin ◽  
Scott K. Thomas ◽  
...  
Keyword(s):  
Steady State ◽  
Heat Pipe ◽  
Quasi Steady State ◽  
Steady State Performance

Experimental Investigations of the Self-Controlled Synchronous Motor Connected to a Three-Phase Line Commutated SCR Inverter

2016 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Tapan Kumar Chakraborty
Keyword(s):  
Steady State ◽  
Synchronous Motor ◽  
The Self ◽  
Experimental Investigations ◽  
Phase Line ◽  
Three Phase ◽  
In Series ◽  
Terminal Voltage ◽  
Excitation Winding ◽  
Steady State Performance

<p>This paper concerns the experimental investigations of the three-phase line commutated SCR inverter fed synchronous motor.  The fabricated system consists of a line-commuted inverter, a three-phase synchronous motor with the excitation winding connected in series to the inverter input, a terminal voltage sensor and a gate-pulse generating circuit. The firing pulses for SCRs of the inverter are generated by the microprocessor in proper sequence with the help of synchronizing signal derived from the terminal voltages of the synchronous machine. The steady state performance characteristics are obtained experimentally using the fabricated system. The experimental results show that a three-phase synchronous motor supplied by a line commutated inverter with the excitation winding connected in series to the dc link provide  excellent characteristics of the conventional dc series motor.</p>

scholarly journals Heating and cooling capacity of phase change material coupled with screen mesh wick heat pipe for thermal energy storage applications

2020 ◽  
Vol 24 (2 Part A) ◽  
pp. 723-734 ◽  
Author(s):  
Rajendran Palappan ◽  
Avadaiappa Pasupathy ◽  
Lazarus Asirvatham ◽  
Tharayil Trijo ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pipe ◽  
Transfer Coefficients ◽  
Maximum Enhancement ◽  
Flow Rates ◽  
Heat Transfer Coefficients ◽  
Heating And Cooling ◽  
Change Material ◽  
Heat Loads

The thermal performance of a phase change material (PCM) heat pipe system is experimentally analysed using acetone as heat pipe fluid in a heat load range of 10-50 W at different flow rates of the condenser coolant. The evaporator of the heat pipe is enclosed in a chamber which filled with a PCM or water. Heat inputs are applied at the evaporator of the heat pipe through the PCM or water. In this study, the heat retention as well as cooling time of the PCM-water are estimated at different heat loads and flow rates of condenser coolant. Similarly, the thermal resistance, evaporator and condenser heat transfer coefficients are also estimated at different heat loads. It is observed that the PCM takes more time during heating and cooling cycles to reach the steady-state temperatures and the temperature values reached during heating are also higher for PCM compared to water. The use of PCM enhances the thermal storage capacity and shows a maximum enhancement of 200% in heat retention time compared to water at 50 W. Moreover, a maximum enhancement of 63.6% is observed in the steady-state temperature of the PCM compared to water. Similarly thermal resistance, evaporator wall temperature and heat transfer coefficients of the heat pipe also vary for PCM and water. The experimental results indicate that PCM or water can be used in this combined system depending upon requirement of thermal storage or electronics cooling.

scholarly journals Modeling of Loop Heat Pipe Thermal Performance

2021 ◽  
Vol 81 (1) ◽  
pp. 41-72
Author(s):  
Inès Gabsi ◽  
Samah Maalej ◽  
Mohamed Chaker Zaghdoudi
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Pipe ◽  
Loop Heat Pipe ◽  
Conductive Heat ◽  
Steady State Operation ◽  
Evaporation Heat ◽  
Compensation Chamber ◽  
Heat Loads ◽  
Good Agreement

The present work deals with the heat transfer performance of a copper-water loop heat pipe (LHP) with a flat oval evaporator in steady-state operation. Modeling the heat transfer in the evaporator was particularly studied, and the evaporation heat transfer coefficient was determined from a dimensionless correlation developed based on experimental data from the literature. The model was based on steady-state energy balance equations for each LHP component. The model results were compared to the experimental ones for various heat loads, cooling temperatures, and elevations, and a good agreement was obtained. Finally, a parametric study was conducted to show the effects of different key parameters, such as the axial conductive heat leaks between the evaporator and the compensation chamber cases, the capillary structure porosity and material, and the groove dimensions.

Simulation of Steady State Surface Temperature Response of a Novel Micro Loop Heat Pipe to Various Heat Loads

2005 ◽  
Author(s):  
M. Ghajar ◽  
J. Darabi
Keyword(s):  
Steady State ◽  
Heat Pipe ◽  
Temperature Response ◽  
Geometric Feature ◽  
Accurate Estimation ◽  
Loop Heat Pipe ◽  
Design Factor ◽  
Temperature Ranges ◽  
Compensation Chamber ◽  
Heat Loads

Numerical investigations have been performed to simulate a novel Micro Loop Heat Pipe (MLHP) under steady state conditions. For most electronics, the maximum working temperature is an important design factor; therefore an accurate estimation of this temperature is crucial. The model predicts the steady state temperature distribution at the surface of the heat source as a function of applied heat loads. This code builds upon a previous code developed by the authors [1], and utilizes a hybridizing of an Alternating Direction Implicit (ADI) Computational Fluid Dynamics (CFD) code and relevant thermodynamic equations. Using this simulation tool, the minimum required compensation chamber cavity has been calculated and checked for various operating temperature ranges. Additionally, the design of the MLHP has been improved by evaluating the effects of the geometric feature variations. Considering the fabrication limitations, some of the optimized geometry dimensions were found to be a groove wall thickness of 2um, a groove width of 7um, a wicking structure length of 500μm, and a vapor line width of 2mm.

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