Question 51 (Textile Technology & Fibre Science)
Under steady-state thermal conditions, the temperature at various locations in a two-plate Togmeter is as shown in the Figure given below. If the thermal resistance of the standard bottom plate is 1.5 K/W, then the thermal resistance (K/W) of fabric specimen (correct up to 1 decimal place) is __.
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As shown in the figure-
Given-
Heater temperature(T1)=36.9 deg C
Standard bottom plate temperature(T2)=36.4 deg C
Top plate temperature(T3)=34.8 deg C
Thermal resistance of standard bottom plate(R)=1.5 K/W
Thermal resistance of fabric specimen(R’)=?
According to heat equations-
(T1-T2) x R’=(T2-T3) x R
(36.9-36.4) x R’=(36.4-34.8) x 1.5
0.5 x R’=1.6 x 1.5
0.5 x R’=2.4
R’=2.4/0.5
R’=4.8 K/W (Ans)