Experimental Investigation Into Thermal Siphon Used as an Intermediate Circuit of an Integrated Cooling System Reactor

Author(s):  
L. A. Adamovich ◽  
B. A. Gabaraev ◽  
S. L. Solovjev ◽  
S. B. Shpansky

In the paper the results of study in heat transfer capacity of the themosyphon mock-up which is considered as an intermediate circuit of the reactor under design, are presented. The mock-up design, the test rig and the experimental results are described. It is shown that the simplest mathematical model describes the processes of power transfer by the thermosyphon under certain conditions.

Author(s):  
Qiang Li ◽  
Yimin Xuan ◽  
Feng Yu ◽  
Junjie Tan

An experimental investigation was performed to study the heat transfer and flow features of Cu-water nanofluids (Cu particles with 26 nm diameter) in a submerged jet impingement cooling system. Three particular nozzle-to-heated surface distances (2, 4 and 6 mm) and four particle volume fractions (1.5%, 2.0%, 2.5% and 3.0%) are involved in the experiment. The experimental results reveal that the suspended nanoparticles increase the heat transfer performance of the base liquid in the jet impingement cooling system. Within the range of experimental parameters considered, it has been found that highest surface heat transfer coefficients can be achieved using a nozzle-to-surface distance of 4 mm and the nanofluid with 3.0% particle volume fraction. In addition, the experiments show that the system pressure drop of the dilute nanofluids is almost equal to that of water under the same entrance velocity.


1985 ◽  
Vol 107 (3) ◽  
pp. 642-647 ◽  
Author(s):  
K. Vafai ◽  
R. L. Alkire ◽  
C. L. Tien

This paper presents an experimental investigation on the effects of a solid impermeable boundary and variable porosity on forced convection in porous media. Emphasis is placed on the channeling effects on heat transfer in packed beds. The local volume-averaging technique is used to establish the governing equations and a numerical scheme is developed which incorporates the boundary and variable porosity effects on heat transfer. The experimental results for the heat flux at the boundary are presented as a function of the pertinent variables in a packed bed. The Nusselt number is found to increase almost linearly with an increase in the Reynolds number based on the pore diameter. The experimental results are found to be in good agreement with the theoretical results which account for the variable porosity effects. A comparison between the numerical and the experimental results demonstrates the importance of boundary and variable porosity effects on heat transfer in variable porosity media.


2008 ◽  
Vol 130 (8) ◽  
Author(s):  
H. B. Ma ◽  
B. Borgmeyer ◽  
P. Cheng ◽  
Y. Zhang

A mathematical model predicting the oscillating motion in an oscillating heat pipe is developed. The model considers the vapor bubble as the gas spring for the oscillating motions including effects of operating temperature, nonlinear vapor bulk modulus, and temperature difference between the evaporator and the condenser. Combining the oscillating motion predicted by the model, a mathematical model predicting the temperature difference between the evaporator and the condenser is developed including the effects of the forced convection heat transfer due to the oscillating motion, the confined evaporating heat transfer in the evaporating section, and the thin film condensation in the condensing section. In order to verify the mathematical model, an experimental investigation was conducted on a copper oscillating heat pipe with eight turns. Experimental results indicate that there exists an onset power input for the excitation of oscillating motions in an oscillating heat pipe, i.e., when the input power or the temperature difference from the evaporating section to the condensing section was higher than this onset value the oscillating motion started, resulting in an enhancement of the heat transfer in the oscillating heat pipe. Results of the combined theoretical and experimental investigation will assist in optimizing the heat transfer performance and provide a better understanding of heat transfer mechanisms occurring in the oscillating heat pipe.


2004 ◽  
Vol 127 (3) ◽  
pp. 532-544 ◽  
Author(s):  
Lamyaa A. El-Gabry ◽  
Deborah A. Kaminski

Measurements of the local heat transfer distribution on smooth and roughened surfaces under an array of angled impinging jets are presented. The test rig is designed to simulate impingement with crossflow in one direction. Jet angle is varied between 30, 60, and 90deg as measured from the target surface, which is either smooth or randomly roughened. Liquid crystal video thermography is used to capture surface temperature data at five different jet Reynolds numbers ranging between 15,000 and 35,000. The effect of jet angle, Reynolds number, gap, and surface roughness on heat transfer and pressure loss is determined along with the various interactions among these parameters.


Author(s):  
K Yamaguchi ◽  
E Shaanika ◽  
M Miki ◽  
M Izumi ◽  
Y Murase ◽  
...  

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