Theoretical and experimental study of capillary constraints on heat transfer in high-temperature heat pipes

1980 ◽  
Vol 38 (5) ◽  
pp. 469-473
Author(s):  
M. N. Ivanovskii ◽  
I. V. Yagodkin ◽  
V. P. Sorokin ◽  
L. M. Kuznetsova
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
High Temperature ◽  
Heat Pipes ◽  
Temperature Heat

Suppression of the Sonic Heat Transfer Limit in High-Temperature Heat Pipes

1989 ◽  
Vol 111 (3) ◽  
pp. 605-610 ◽  
Author(s):  
Flavio Dobran
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Pipes ◽  
Vapor Flow ◽  
Transport Capacity ◽  
Flow Area ◽  
Temperature Heat ◽  
Liquid Evaporation ◽  
Heat Transfer Limit ◽  
Axial Heat

The design of high-performance heat pipes requires optimization of heat transfer surfaces and liquid and vapor flow channels to suppress the heat transfer operating limits. In the paper an analytical model of the vapor flow in high-temperature heat pipes is presented, showing that the axial heat transport capacity limited by the sonic heat transfer limit depends on the working fluid, vapor flow area, manner of liquid evaporation into the vapor core of the evaporator, and lengths of the evaporator and adiabatic regions. Limited comparisons of the model predictions with data of the sonic heat transfer limits are shown to be very reasonable, giving credibility to the proposed analytical approach to determine the effect of various parameters on the axial heat transport capacity. Large axial heat transfer rates can be achieved with large vapor flow cross-sectional areas, small lengths of evaporator and adiabatic regions or a vapor flow area increase in these regions, and liquid evaporation in the evaporator normal to the main flow.

Numerical Simulation Study on Local Enhanced Heat Transfer for High Temperature Heat Pipe Heat Exchanger

2011 ◽  
Vol 396-398 ◽  
pp. 897-903
Author(s):  
Shi Mei Sun ◽  
Jing Min Zhou
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Exchanger ◽  
Temperature Distribution ◽  
Heat Pipe ◽  
Heat Pipes ◽  
Fluid Temperature ◽  
Temperature Heat ◽  
High Temperature Heat Pipe ◽  
Pipe Heat

A High Temperature Heat Pipe Heat Exchanger Consists of Heat Pipes Filled with Different Working Media inside. in Different Temperature Zones, Heat Pipes with Different Working Media Are Linked Safely by Controlling the Vapor Temperature, the Media inside the Heat Pipe. the Vapor Temperature inside the Pipe Is Heavily Affected by the Temperature Field of Fluid outside the Heat Pipes and the Heat Transfer Performance inside the Heat Pipe, while the Heat Transfer Performance inside the Pipe in Turn Has a Bearing on the Temperature Distribution of Fluid outside the Pipe. to Coordinate the Fluid Temperature Distribution both inside and outside the Pipes, Study on Local Heat Transfer Enhancement Has Been Conducted on High Temperature Heat Pipe Heat Exchanger in this Article, and Cfd Computational Software Was Used to Make Rational and Accurate Prediction of Fluid Temperature Distribution both inside and outside the Pipes, so as to Provide Economic and Reliable Design Basis for High Temperature Heat Pipe Heat Exchanger.

Experimental study of viscosity characteristics of high-temperature heat transfer molten salts

2011 ◽  
Vol 54 (11) ◽  
pp. 3022-3026 ◽  
Author(s):  
YongChang Chen ◽  
YuTing Wu ◽  
Nan Ren ◽  
ChongFang Ma
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
High Temperature ◽  
Molten Salts ◽  
Temperature Heat

High-temperature heat pipes investigation at radial heat transfer

1978 ◽  
Author(s):  
V. TOLUBINSKII ◽  
E. SHEVCHUK ◽  
V. MAKAROV ◽  
A. TOMASHEVSKII
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Pipes ◽  
Temperature Heat ◽  
Radial Heat

Experimental Investigations of Radially Rotating Miniature High-Temperature Heat Pipes

2000 ◽  
Vol 123 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Jian Ling ◽  
Yiding Cao ◽  
Alex P. Lopez
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Pipe ◽  
High Speed ◽  
Thermal Conductance ◽  
Heat Pipes ◽  
Experimental Investigations ◽  
Temperature Heat ◽  
Heat Transfer Capacity ◽  
High Temperature Heat Pipe

A radially rotating miniature high-temperature heat pipe employs centrifugal force to return the condensate in the condenser section to the evaporator section. The heat pipe has a simple structure, very high effective thermal conductance and heat transfer capacity, and can work in hostile high-temperature environments. In this research, a high-speed rotating test apparatus and data acquisition system for radially rotating miniature high-temperature heat pipes are established. Extensive experimental tests on two heat pipes with different dimensions are performed, and various effects of influential parameters on the performance characteristics of the heat pipes are investigated. The ranges of the important parameters covered in the current experiments are: 470⩽ω2Za¯/g⩽1881; 47 W⩽Q⩽325W; di=1.5 and 2 mm; and 1.05×10−3m3/s⩽W⩽13.4×10−3m3/s. The experimental data prove that the radially rotating miniature high-temperature heat pipe has a high effective thermal conductance, which is 60–100 times higher than the thermal conductivity of copper, and a large heat transfer capacity that is more than 300 W. Therefore, the heat pipe appears to be feasible for cooling high-temperature gas turbine components.

Analyses of Radially Rotating High-Temperature Heat Pipes for Turbomachinery Applications

1999 ◽  
Vol 121 (2) ◽  
pp. 306-312 ◽  
Author(s):  
J. Ling ◽  
Y. Cao ◽  
W. S. Chang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Heat Pipe ◽  
Turbine Blade ◽  
Heat Pipes ◽  
Pipe Length ◽  
Turbine Blade Cooling ◽  
Rotating Speed ◽  
Blade Cooling ◽  
Temperature Heat

A set of closed-form solutions for the liquid film distributions in the condenser section of a radially rotating miniature heat pipe and for the vapor temperature drop along the heat pipe length are derived. The heat transfer limitations of the heat pipe are analyzed under turbine blade cooling conditions. Analytical results indicate that the condenser heat transfer limitation normally encountered by low-temperature heat pipes no longer exists for the high-temperature rotating heat pipes that are employed for turbine blade cooling. It is found that the heat pipe diameter, radially rotating speed, and operating temperature are very important to the performance of the heat pipe. Heat transfer limitations may be encountered for an increased heat input and rotating speed, or a decreased hydraulic diameter. Based on the extensive analytical evaluations, it is concluded that the radially rotating miniature heat pipe studied in this paper is feasible for turbine blade cooling applications.

Effect of Absorptive Coating of the Hot Fluid Passage of a Heat Exchanger Employing Exergy-Optimized Pin Fins in High Temperature Applications

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Nwosu P. Nwachukwu ◽  
Samuel O. Onyegegbu
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Simple Relation ◽  
Base Temperature ◽  
Minimum Entropy ◽  
Pin Fin ◽  
Temperature Heat ◽  
Pin Fins ◽  
Minimum Entropy Generation ◽  
Fluid Parameters

An expression for the optimum pin fin dimension is derived on exergy basis for a high temperature exchanger employing pin fins. The present result differs from that obtained by Poulikakos and Bejan (1982, “Fin Geometry for Minimum Entropy Generation in Forced Convection,” ASME J. Heat Transfer, 104, pp. 616–623) for a low temperature heat recovery application. Also, a simple relation is established between the amounts the base temperature of the optimized pin fin is raised for a range of absorptive coating values. Employing this relation, if the absorptivity of the coating, the plate emissivity, the number of protruding fins, and some area and fluid parameters are known, the corresponding value for the base temperature of the fin is immediately obtained. The analysis shows that the thermal performance of the exchanger improves substantially with a high absorptivity coating hence can be seen as a heat transfer enhancement feature of the exchanger operating with radiation dominance.

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