Bissoy.com
Doctors Medicines MCQs Q&A

The calculation of heat transmission by convection is based on the determination of a Nusselt number or convective film coefficient. To that goal, which of the following strategies have been proposed (i) Non-dimensional analysis and experimental correlations (ii) Hydrodynamic concept of velocity boundary layer (iii) Reynolds similarity between the mechanism of fluid friction in the boundary layer and the transfer of heat by convection Identify the correct one

The calculation of heat transmission by convection is based on the determination of a Nusselt number or convective film coefficient. To that goal, which of the following strategies have been proposed (i) Non-dimensional analysis and experimental correlations (ii) Hydrodynamic concept of velocity boundary layer (iii) Reynolds similarity between the mechanism of fluid friction in the boundary layer and the transfer of heat by convection Identify the correct one Correct Answer ii and iii

It should be a dimensional analysis and experimental correlations.

Related Questions

The determination of a value of Nusselt number or the convective film coefficient forms a basis for the computation of heat transfer by convection. Towards that end, following approaches have been suggested (i) Non-dimensional analysis and experimental correlations (ii) Hydrodynamic concept of velocity boundary layer (iii) Reynolds similarity between the mechanism of fluid friction in the boundary layer and the transfer of heat by convection Identify the correct one
For a laminar flow of fluid in a circular tube, 'h₁' is the convective heat transfer co-efficient at velocity 'V₁'. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is
For a laminar flow of fluid in a circular tube, 'h1' is the convective heat transfer co-efficient at velocity 'V1'. If the velocity is reduced by half and assuming the fluid properties are constant, the new convective heat transfer co-efficient is
Experimental results indicate that the local heat transfer coefficient h g for flow over a flat plate with an extremely rough surface is approximated by the relation h x = a x -0.12 Where a is a constant coefficient and x is distance from the leading edge of the plate. What is the relation between this local heat transfer coefficient and the average heat transfer coefficient for a plate of length x?
A stream of air at 100 kPa pressure and 300 K is flowing on the top surface of a thin flat sheet of solid naphthalene of length 0.2 m with a velocity of 20 m/sec. The other data are: Mass diffusivity of naphthalene vapor in air = 6 * 10 –6 m2/sec Kinematic viscosity of air = 1.5 * 10 –5 m2.sc Concentration of naphthalene at the air-solid naphthalene interface = 1 * 10 – 5 kmol/m3 Calculate the overage mass transfer coefficient over the flat plate. Note: For heat transfer over a flat plate, convective heat transfer coefficient for laminar flow can be calculated by the equation. Nu = 0.664 ReL1/2 Pr1/3 you may use analogy between mass and heat transfer.
Air enters a rectangular duct measuring 30 cm by 40 cm with a velocity of 8.5 m/s and a temperature of 40 degree Celsius. The flowing air has a thermal conductivity 0.028 W/m K, kinematic viscosity 16.95 * 10 -6 m2/s and from empirical correlations the Nusselt number has been approximated to be 425. Find out the flow Reynolds number
While discussing about friction, a teacher gave a number of examples to explain the concept. Some of the examples where friction is useful in our day-to-day life as quoted by the teacher are given below : A. We are able to write because of friction between the tip of the pen and the paper. B. We are able to walk because of friction between our feet and the ground. C. A ball thrown vertically upwards comes back to us due to friction. D. We are able to stop a moving vehicle by applying brakes because of friction. The correct examples were
Which one of them is a correct combination? 1) Boundary Lubrication i) Dimensionless film thickness < 1 2) Hydrodynamic Lubrication ii) Dimensionless film thickness lies between 1 and 3 3) Mixed Lubrication iii) Dimensionless film thickness lies between 3 and 5 4) Elastohydrodynamic Lubrication iv) Dimensionless film thickness is greater than 5
Five theatres PVR, DT, Chanakya, Regal and Maratha Mandir screen two out of ten films based on Romance, Thriller, Horror, Adventure, Children, Drama, Documentary, History, Religion and Cartoon. Each theatre exhibits only two films and allots two different slots for them, wherein slot I is before slot II. Chanakya screens a Horror film in the first slot, while Maratha Mandir exhibits a Historical film in the second slot. DT exhibits a thriller film in the second slot and Regal exhibits a documentary film. Drama must be exhibited only in the second slot. The children’s film and the Cartoon film are exhibited in the same theatre while the religious film is not in the first slot. If Chanakya screens a Religious film in its second slot, then which of the films can be screened by theatre Regal?
A horizontal heated plate at 200 degree Celsius and facing upwards has been placed in still air at 20 degree Celsius. If the plate measures 1.25 m by 1 m, make calculations for the heat loss by natural convection. The convective film coefficient for free convection is given by the following empirical relation h = 0.32 (α) 0.25 W/m2 K Where α is the mean film temperature in degrees kelvin