GATE ME
Heat Transfer
Convection
Previous Years Questions

## Marks 1

Grashof number signifies the ratio of
The ratio of momentum diffusivity $$\left( \upsilon \right)$$ to thermal diffusivity $$\left( \alpha \right),$$ is called
In the laminar flow of air $$(Pr=0.7)$$ over a heated plate, if $$\delta$$ and $${\delta _T}$$ denote, respectively the hydrodynamic and thermal boun...
The Blasius equation related to boundary layer theory is a
For flow of viscous fluid over a flat plate, if the fluid temperature is the same as the plate temperature, the thermal boundary layer is
Match Group $$A$$ with Group $$B$$ Group-A $$P:$$$$\,\,\,\,\,\,\,$$ Biot number $$Q:$$$$\,\,\,\,\,\,\,$$ Grashof number $$R:$$$$\,\,\,\,\,\,\,$$ Pr...
Consider a two-dimensional laminar flow over a long cylinder as shown in the figure below. The free stream velocity is $${U_\infty }$$ and the free ...
For laminar forced convection over a flat plate, if the free stream velocity increases by a factor of $$2,$$ the average heat transfer coefficient
A coolant fluid at $${30^ \circ }C$$ flows over a heated flat plate maintained at a constant temperature of $${100^ \circ }C$$. The boundary layer tem...
For flow of fluid over a heated plate, the following fluid properties are known: Viscosity $$=0.001Pa.s;$$ Specific heat at constant pressure $$=1$$ $... Heat transfer coefficients for free convection in gasses, forced convection in gases and vapors, and for boiling water lie, respectively, in the range... For air near atmospheric condition flowing over a flat plate the laminar thermal boundary layer is thicker than hydrodynamic boundary layer In pool boiling the highest $$HTC$$ occurs in For the fluid flowing over a flat plate with Prandtle number greater than unity, the thermal boundary layer for laminar forced convection ## Marks 2 A fluid (Prandtl number, $$Pr=1$$) at $$500$$ $$K$$ flows over a flat plate of $$1.5$$ $$m$$ length, maintained at $$300$$ $$K.$$ The velocity of the ... For flow through a pipe of radius $$R,$$ the velocity and temperature distribution are as follows: $$U\left( {r,x} \right) = {C_1}$$ and $$T\left( {r,... Water flows through a tube of diameter$$25mm$$at an average velocity of$$1.0m/s.$$The properties of water are$$\rho = 1000\,\,kg/{m^3},\mu ... Consider one dimensional steady state heat conduction across a wall (as shown in figure below) of thickness $$30$$ $$mm$$ and thermal conductivity $$1... The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by$${{{T_w} - T} \over {{T_w} - {T_\infty... The ratios of the laminar hydrodynamic boundary layer thickness to thermal boundary layer thickness of flows of two fluids $$P$$ and $$Q$$ on a flat p... Match the following List-$${\rm I}$$ $$P.$$ Compressible flow $$Q.$$ Free surface flow $$R.$$ Boundary layer flow $$S.$$ Pipe flow $$T.$$ Heat convec... The temp distribution within the Laminar thermal boundary layer over a heated isothermal flat plate is given by $$\left( {T - {T_w}} \right)/\left( {... The average heat transfer coefficient on a thin hot vertical plate suspended in still air can be determined from observations of the change in plate t... An un-insulated air conditioning duct of rectangular cross section$$1\,\,m \times 0.5\,m,$$carrying air at$${20^ \circ }C$$with a velocity of$$10... An un-insulated air conditioning duct of rectangular cross section $$1\,\,m \times 0.5\,m,$$ carrying air at $${20^ \circ }C$$ with a velocity of $$10... Consider a laminar boundary layer over a heated flat plate. The free stream velocity is$${U_\infty }.$$At some distance$$x$$from the leading edge ... The properties of mercury at$$300K$$are : density$$ = 13529kg/{m^3},{C_P} = 0.1393kJ/kgK,$$dynimic viscosity$$ = 0.1523\,\, \times \,\... Water (Prandtl number $$=6$$ ) flows over a flat plate which is heated over the entire length. Which one of the following relationship between the hyd... Match List - $${\rm I}$$ with List - $${\rm II}$$ and select the correct answer using the code given below the Lists: List - $${\rm I}$$ $$A.$$ Grash... A fluid flowing over a flat plate has the following properties: dynamic viscocity $$= 25 \times {10^{ - 6}}\,\,kg/ms,$$ specific heat $$=2.0$$$\$kJ/...
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