Study of natural convection heat transfer in a rectangular enclosure from one cooled side wall

Abstract

An experimental investigation of natural convection heat transfer in rectangular enclosure from one cooled veJ1ical side wall is carried out. [n the experiment the side wall is cooled by a thermoelcctric module (TEM). The measurements cover the temperatures of the cold plate and air in the enclosures at different interval of time at 14 different locations which are measured and recorded by data acquisition system. The power consumed by a thermoelectric module (TEM) during the transient and steady state conditions is also recorded. [n an experiment lasting I hour. the enclosure air is cooled down to a minimum of 5"C, when the cold wall temperature is -40c. With time, temperatures of both cold wall and air within the enclosure decrease asymptotically to a steady state value. From the temperature distribution data, stratification within the enclosure is observed. The stratification indicator y is estimated at three different horizontal distances from the cold plate for the time interval of 15, 25, 50, 60 and 80 minutes and found to be decreased with the time. Heat transfer rate, heat transfer coefficient, Nusselt number and Rayleigh number arc calculated from the measured experimental data during transient and steady state regime. The Rayleigh number and Nusselt number cover the range, 1.47 x 10" to 3.08 x 107 and 18.55 to 33.50 respectively. From the experimental results a correlation is developed in terms of Nusselt number and Rayleigh number which is found to be capable of correlating all experimental data within:t 15%.