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%.
