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Heat Pipe Science and Technology, An International Journal

ISSN Print: 2151-7975
ISSN Online: 2151-7991

Heat Pipe Science and Technology, An International Journal

DOI: 10.1615/HeatPipeScieTech.v5.i1-4.390
pages 351-357

MEASUREMENT OF THERMAL CONDUCTIVITY, PORE SIZE, PERMEABILITY AND COEFFICIENT OF THERMAL EXPANSION OF POROUS NICKEL WICK FOR LHPs

Arpana Prasad
Thermal Systems Group, ISRO Satellite Centre, Bangalore-560017, India
A. R. Anand
Thermal Systems Group, ISRO Satellite Centre, Bangalore-560017, India
D. Raghavendra Kumar
Thermal Systems Group, ISRO Satellite Centre, Bangalore-560017, India
V. Ramakrishnan
Thermal Systems Group, ISRO Satellite Centre, Bangalore-560017, India
Amrit Ambirajan
Thermal Systems Group, ISRO Satellite Centre, Indian Space Research Organization, Bangalore, INDIA
D. Kumar
Thermal Systems Group, ISRO Satellite Centre, Indian Space Research Organization P.O. Box 1795, Vimanapura Post, HAL Airport Road, Bangalore - 560017
Pradip Dutta
Dept. of Mechanical Engineering, Indian Institute of Science INDIA

ABSTRACT

The properties of an LHP wick are critical to its heat transport capacity. This paper presents experimental measurements of thermal conductivity, pore size, permeability and coefficient of thermal expansion (CTE) of a porous Nickel wick prepared by sintering method. The result reveals that under vacuum environment, the experimentally measured thermal conductivity of porous Nickel wick shows decreasing trend with increase in temperature and its room temperature value is ~9.93 Wm-1K-1. An analytical study was performed to find a suitable model for predicting the effective thermal conductivity. This study shows that under vacuum condition Hadley model gives better prediction. This model was also validated with other set of porous Ni sample data and found to be in good agreement with experimental thermal conductivity result. The maximum pore size of this porous Nickel wick is 4.8μm and porosity is ~63.5%. Its liquid permeability is 5.3×10-13m2 and gas permeability value varies between 1.9×10-13m2 and 5.8×10-13m2 for the flow velocity between 0.06m/s and 0.7m/s. The average CTE value of porous nickel sample is ~11.8μm/m°C in the temperature range of -100 to 200°C.