OCR Text |
Show Results & Discussion A series of experiments were performed in a furnace enclosure where batch operating conditions such as heating rate, load properties and geometry and furnace temperature were simulated. The objective of the tests was to evaluate improvements in the convective heat transfer coefficient. These improvements would be determined by comparison of the thermal response of the furnace load to the energy input via the combustion system for both the AM and FM furnace temperature control techniques. The geometry of the furnace enclosure and position of the thermocouple in the load is indicated in Figures 5 and 6 respectively. The furnace load consisted of 2500 Lbs. of steel consisting of four different type of parts, that is, machined solid parts and annular rings ranging in mass from 1.48 to 3.96 Lbs. The assorted parts were randomly distributed in four alloy steel containers. The baskets were supported by columns of firebrick and centered vertically so as to maintain equal space above and below the load. In each test, the load mass and position in the enclosure were constant. In order to quantify the improvements in load temperature uniformity resulting from FM temperature control, the standard deviation was calculated from the thermocouple readings of load temperatures and plotted as a function of time. As indicated in Figure 7, FM control results in lower standard deviations for both thermal cycles considered 7-10 |