Resistivity Measurement of Irregularly-Shaped Graphite Heater: A Simulation and Experimental Study

Herein, we addressed the resistivity measurement of the irregularly-shaped heaters, made of isostatic-pressure graphite and widely used in high temperature (> 1600℃) vacuum furnace. The voltage distributions in the heaters, particularly in the rectangular graphite plates with and without twin electric connection holes, were mathematically modeled, numerically simulated in finite element method with ANSYS software and experimentally evaluated. The discrepancy between the simulated and measured voltages was 0. 6% for the graphite plate without twin-hole, whereas for the graphite plate with twin-hole the largest error, near the high voltage end, was 5%. In addition, the influence of the contact area and position of the newly-designed pair of electric clamps on the accuracy of resistivity was investigated for design optimization. We suggest that the simulated results be of some technological interest in fabrication and applications of graphite heaters.