Figure 1. This graph was digitized and plotted in Excel. A line was fitted to the data points and the equation for the fitted line was then used to calculate values that corresond to this graph.
Compute the surface temperature of a 1/12 inch diameter resistance wire generating heat at the rate of 236.77 Btu/hr per foot length. The ambient air temperature is 66 deg F. Neglect the radiation heat loss.
The solution is approached through an iterative process. An initial value of ther surface temperature is assumed and the heat rate required to maintain this temperature is calculated. This procedure is repeated until the calculated value of the heat rate equal the given value.
In Matlab:
The solution to this problem can be found by simply using the function guess.m
>> Temp=guess(257.8,66,1200)
ans = 1733.4 F
The function, guess.m uses another function called data.m in order to interpolate the data given in Table 1. This data is required in the calculations to find temperature, but because the process is iterative, new values for different variables must be obtained for each guessed temperature.
