ME 340 Project: Fall 2010 Heat Transfer in a Rice Cooker Brad Glenn Mason Campbell

Introduction Knowing the heating power of a rice cooker, we will heat a known mass of water and predict the outer surface temperature of the pot. In order to accomplish this we need to calculate a convection coefficient and the overall thermal resistance between the water and the surface of the pot.

Set up of the Problem Create a thermal circuit of the conduction through the pot and convection between the pot and the water. – Assuming natural convection, determine the convection coefficient of the water – Then determine the overall thermal resistance of the circuit Assuming a constant heat rate, determine the temperature of the pot surface after 30 seconds. (See Appendix for details)

Solution Temp of water initially T1=38.3 C Heat rate of rice cooker q=275 W Convection coefficient h= W/m^2 K Thermal Resistance Rtot= K/W Predicted temp of pot surface Ts=69.5 C

Results of Experiment Measured value of Ts=75.8 C

Conclusions We think one of the biggest sources of error in our assumptions was that our convection coefficient was too high resulting in lower predicted surface temperature. – One possible reason for this error was that we had to assume the inner surface temperature when calculating the Grashof number. – More iterations are recommended for a more accurate result.

Appendix