Heat and Mass Transfer The most commonly used method for the design of duct size is the Static regains method Dual or double method Equal friction method Velocity reduction method Static regains method Dual or double method Equal friction method Velocity reduction method ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The logarithmic mean temperature difference (tm) is given by (where Δt1 and Δt2 are temperature differences between the hot and cold fluids at entrance and exit) tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 tm = loge (Δt1/Δt2)/ (Δt1 - Δt2) tm = tm = (Δt1 - Δt2) loge (Δt1/Δt2) tm = (Δt1 - Δt2)/ loge (Δt1/Δt2) tm = loge (Δt1 - Δt2)/ Δt1/Δt2 ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer Reynolds number is the ratio of None of these Inertia force to viscous force Energy transferred by convection to that by conduction Kinematic viscosity to thermal diffusivity None of these Inertia force to viscous force Energy transferred by convection to that by conduction Kinematic viscosity to thermal diffusivity ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer A designer chooses the values of fluid flow rates and specific heats in such a manner that the heat capacities of the two fluids are equal. A hot fluid enters the counter flow heat exchanger at 100°C and leaves at 60°C. A cold fluid enters the heat exchanger at 40°C. The mean temperature difference between the two fluids is 20°C 60°C 40°C 66.7°C 20°C 60°C 40°C 66.7°C ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The value of the wave length for maximum emissive power is given by Planck’s law Wine’s law Kirchhoff’s law Stefan’s law Planck’s law Wine’s law Kirchhoff’s law Stefan’s law ANSWER DOWNLOAD EXAMIANS APP
Heat and Mass Transfer The ratio of the energy absorbed by the body to total energy falling on it is called Emissivity Absorptivity Emissive power Absorptive power Emissivity Absorptivity Emissive power Absorptive power ANSWER DOWNLOAD EXAMIANS APP
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