Variable-conductance heat pipe

Liquid fertilizers, potassium orthophosphates in, 20 637 Liquid-film coefficient, 15 695 Liquid filtration, 11 322-323 Liquid flavor forms, 11 576-577 Liquid flow control, in variable-conductance heat pipes, 13 233 Liquid fluidization, 11 791-792 Liquid food ingredients, encapsulated,... 

There are a number of different ways to classify heat pipes, but perhaps the two most important categories are the variable-conductance heat pipes (those in which the magnitude and/or direction of the heat transfer can be controlled) and micro-heat pipes (those that are so small that the mechanisms controlling their operation are significantly different from those in more conventional heat pipes). 

R. I. J. Van Buggenum and D. H. V. Daniels, Development, Manufacturing and Testing of a Gas Loaded Variable Conductance Heat Pipe, Proc. 6th Int. Heat Pipe Conf, Grenoble, France, pp. 242-249,1987. 

Y. Sakuri, H. Masumoto, H. Kimura, M. Furukawa, and D. K. Edwards, Flight Experiments for Gas-Loaded Variable Conductance Heat Pipe on ETS-III Active Control Package, Proc. 5th Int. Heat Pipe Conf, Tsukuba, Japan, pp. 26-32,1984. 

A variable-conductance heat pipe and gas gap filling system, as two independent systems for heat dissipation to the environment ... 

VCHP= Variable Conductance Heat Pipe C-C= Carbon-Carbon... 

For loss of coolant accident, it has been assumed that coolant is unavailable in the upper plenum, core and lower plenum of the reactor. Due to the absence of a heat removal medium, temperatures of the core will start increasing, leading to heating of all core components. The negative void reactivity coefficient will limit the power and thus, the temperature of the core components. The neutronically limited power would reach 200 kW(th). For this case, a system of 12 variable-conductance heat pipes, made of a carbon-carbon composite with a metallic liner, has been provided. These heat pipes penetrate the core. The condenser end of these heat pipes extends beyond the upper plenum and the interface vessels of heat-utilizing systems to the atmosphere. At the condenser end, these heat pipes have radiator fins to dissipate heat to the atmosphere. In case of a postulated accident due to loss of load or loss of coolant, core temperature will start increasing. As long as the temperature of the core is within... 

K, these heat pipes will continue to transfer heat to the interface vessels of heat utilizing systems. Since the heat pipes are a variable conductance type, they will not allow temperatures of the core to increase beyond 1273 K. 

Thin, circular metal fins are used to augment heat transfer from circular pipes, for example, in home heating units. For such thin fins, heat is conducted mainly in the radial direction by the metal, losing heat to the atmosphere by way of a constant heat transfer coefficient h. In Problem 3.3, we introduced the follow variables... 

The geometric variable is pipe diameter D [L]. The material variables are fluid density p [L M], fluid dynamic viscosity p [L MT ], fluid heat capacity Cp [L MT 0 ], fluid thermal conductivity k [LMT 0 ], and fluid heat transfer coefficient h [MT 9 ]. The process variables are fluid velocity v [LT ], average fluid temperature Tavc [6]. and pipe wall temperature Tpipe [0]. The Dimensional Table is... 

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