Heat and Mass Transfer The heat transfer by conduction through a thick cylinder (Q) is given by (where T₁ = Higher temperature, T₂ = Lower temperature, r₁ = Inside radius, r₂ = Outside radius, l = Length of cylinder, and k = Thermal conductivity) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) Q = 2.3 log (r₂/r₁)/[2πlk (T₁ - T₂)] Q = = 2πlk/2.3 (T₁ - T₂) log (r₂/r₁) Q = [2πlk (T₁ - T₂)]/2.3 log (r₂/r₁) Q = [2π (T₁ - T₂)]/2.3 lk log (r₂/r₁) ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Unit of thermal diffusivity is m²/hr °C m²/hr kcal/m² hr kcal/m. hr °C m²/hr °C m²/hr kcal/m² hr kcal/m. hr °C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Log mean temperature difference in case of counter flow compared to parallel flow will be Depends on other factors Same Less More Depends on other factors Same Less More ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The automobile radiator is a heat exchanger of Regenerator type Counter flow type Parallel flow type Cross flow type Regenerator type Counter flow type Parallel flow type Cross flow type ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Two balls of same material and finish have their diameters in the ratio of 2: 1 and both are heated to same temperature and allowed to cool by radiation. Rate of cooling by big ball as compared to smaller one will be in the ratio of 0.16736111111111 0.042361111111111 0.084027777777778 0.043055555555556 0.16736111111111 0.042361111111111 0.084027777777778 0.043055555555556 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The concept of overall coefficient of heat transfer is used in heat transfer problems of Conduction Conduction and convection Radiation Convection Conduction Conduction and convection Radiation Convection ANSWER DOWNLOAD EXAMIANS APP
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