Heat transfer analysis of a cavity-type solar radiometer

A heat transfer analysis based on the fundamental governing equations is presented for the cone and resistor of a cavity-type solar radiometer. The operation of the radiometer is divided into three periods: very small values of time, transient period, and steady state. For very small values of time, the governing equation is the wave equation. Oscillations can occur during this period if the heat sink is subjected to an impulse. The governing equation for the transient problem is the familiar parabolic differential equation, and the solution is obtained by solving the simultaneous partial differential equations by means of the Laplace transform. The steady-state analysis leads to the derivation of a simple expression describing the sensitivity of the radiometer as a function of its physical and geometric parameters. The effect of various heat losses on performance is discussed and illustrated graphically.