The invention discloses an optimum design method for a two-dimensional heat transfer model of a phase change heat storage device. The optimum design method for the two-dimensional heat transfer model of the phase change heat storage device is used in a returning process of a reused aircraft; metal ribs and paraffin phase change materials are stored in the phase change heat storage device; difference between the thermal conductivity, the density and the specific heat of the metal ribs and the thermal conductivity, the density and the specific heat of the paraffin phase change materials is large; the solid phase change materials are changed into liquid after absorbing heat, namely, the phase change materials can be in a solid state or a liquid state; the heat exchange relation of the phase change materials is different from that of the metal ribs; and the two-dimensional heat transfer model is divided into a bottom plate, the paraffin phase change materials, the metal ribs and an upper cover plate according to the heat exchange relation of the phase change heat storage device. The optimum design method comprises the following steps of establishing a heat transfer equation according to a heat exchange mode between the phase change materials and a rib interface; solving a function relationship equation between rib parameters and design inputting parameters by using a finite difference method; and determining design variable, an objective function, a constraint condition and a relation of the design variable, the objective function and the constraint condition to obtain the thicknesses of the ribs and the optimal solution of a distance between each two adjacent ribs and finish an optimum design scheme of the phase change device.

Optimum design method for two-dimensional heat transfer model of phase change heat storage device

In this paper, we propose a practical simulation method for designing Loop Heat Pipe (LHP) which is applied to cooling system for electronic devices. To realize rapid evaluation of cooling performance of LHP, the proposed performance estimation method calculates maximum heat transfer of LHP using 1D thermal-fluid network analysis. However, it is difficult to simulate phase-change of working fluid in LHP accurately with 1D model, since each component of LHP is modeled into a simple 1D network and its detailed shape is not considered enough. Especially, evaporator wick is indispensable component of LHP for determining its maximum heat transfer, and it is required to predict wick dry-out, where working fluid is dried in many pores of wick and LHP does not work as a result. The proposed simulation method introduces a wick pore inactivation model which depends on both input heat and wick pore diameter distribution to consider wick dry-out. The inactivation model applied to calculating wick permeability which determines pressure loss of wick. By fitting the wick permeability model to measured temperature distribution and maximum heat transfer of a LHP prototype for server systems, we show that our model estimates maximum heat transfer within allowable error compared to the experimental value.

A performance estimation method of Loop Heat Pipe with a wick permeability model considering dry-out of wick pores

2107 Development of a Design System for Phase Change Cooling of Electronic Devices

PROBLEM TO BE SOLVED: To provide are a heat transport performance analysis method and a heat transport performance analysis device capable of highly accurately evaluating heat transport performance of a heat pipe with a low calculation costSOLUTION: A heat transport performance analysis method includes: a step of reading, by an input data reading unit (12), an initial parameter containing dimension information and physical property value information of a heat pipe (1); a step of creating, by a model creation unit (14), an analysis model in which the heat pipe is divided into a plurality of regions based on the initial parameter; and a step of calculating, by an equation solver (16), a heat passing amount of a boundary between regions in the analysis model based on the initial parameter; where the step of creating an analysis model contains a step of dividing the heat pipe into three regions, a pipe wall of a pipe (2), a fluid film region of a working fluid (8) flowing along an inner surface of the pipe wall, and a central volume region on a radially inner side of the pipe than the fluid film regionSELECTED DRAWING: Figure 5

Heat transport performance analysis method and heat transport performance analysis device

PROBLEM TO BE SOLVED: To enable the creation of an accurate analysis model in a short period.SOLUTION: A one-dimensional model creation unit 12 creates a one-dimensional model M2 showing a channel of a coolant from a three-dimensional mode M1 of a heat transport device. A node setting unit 13 sets nodes N in each of which analysis information used for thermal analysis is allocated to the one-dimensional model M2. An analysis unit 14 repeatedly performs analysis calculation based on the analysis information allocated to the nodes N while causing the node setting unit 13 to increase the number of nodes N until the analysis accuracy is guaranteed in a result of the analysis.

Analysis processing apparatus, analysis processing method, and program

PROBLEM TO BE SOLVED: To make it possible to achieve more accurate performance prediction in rapid one-dimensional analysis.SOLUTION: The object is attained by a performance prediction method executed by a computer, the method including the procedures of: calculating permeability by applying an inactivation ratio indicating a probability that a wick pore does not act as a capillary on the basis of design variables related to a wick and a radiator of a cooling system; calculating a thermal conductance of the radiator on the basis of the design variables; performing a one-dimensional thermal fluid network analysis using the permeability and the thermal conductance as analysis parameters to calculate a capillary force of the wick and pressure loss of the cooling system, thereby determining maximum heat transfer.

Izumi Nitta

Papers

A performance estimation method of Loop Heat Pipe with a wick permeability model considering dry-out of wick pores

2107 Development of a Design System for Phase Change Cooling of Electronic Devices

Analysis processing apparatus, analysis processing method, and program

Performance prediction method and performance prediction apparatus