HEAT PIPE STUDIES

Abstract

This thesis presents an experimental investigation on the performance of the heat pipe under the conditions of various Orientations, working fluid quantities, heat inputs and the coolant flow rates, Heat pipe was a stainless steel pipe having a wick which was made by wrapping several layers of cotton-cloth over a tube, perforated at both ends. The pipe was of 3Q rrm outside dia-meter and 620 mm long, having evaporator section of 1:50 mmIr adiabatic section of 370 in and condenser section of 100 mm, ahe evaporator section had an electric heater which was made by wrapping nichrome wire coils over the evaporator section length, The condenser section had a swirling chamber for the circulation of the coolant (water) around it. Distilled water was used as the working f 1iid. Calibrated Copper -Constantah thermocouples (24 gauge) mounted along the length of the heat pipe measured the temperature in the vapour core and that of the wick with the help of a digital multiineter: The coolant flow rate was measured by means of a cali brated rotarneter and the heat input by a calibrated wattmeter. Heat pipe orientation was Varied from Oo to .10° with respect to horizontal axis. The coolant flow rate varied from 111.25 c.c. to 191 cc./min. heat input from 4wv to BOW and the working fluid quantity from 15.0 c.c. to 170 c.c. The temperature profiles along the length of the heat pipe during transient and steady state conditions were found to have ii almost uniform temperatures in the evaporator section and a sharp -decrease in the condenser section. The temperature along the heat pipe decreased with the increase in coolant flow rate and also with the decrease in heat input. This resulted in a linear variation of the performance of heat pipe with .the heat input, orientation of the heat pipe affected the vapour-temperature significar t-ly ; temperature increased in the evaporator section but decreased in the condenser section when the heat pipe was tilted against gravity (evaporator section above the condenser section), The performance of the heat pipe was found to decrease with the increase in tilt of the heat pipe. The working fluid quantity also changed the vapour temperature and the performance of the heat pipe.