Heat Transfer Multipass heat exchangers are used For low heat load To obtain higher heat transfer co-efficient and shorter tube Because of simplicity of fabrication To reduce the pressure drop For low heat load To obtain higher heat transfer co-efficient and shorter tube Because of simplicity of fabrication To reduce the pressure drop ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for Cylinder Cube Equal for all the three Sphere Cylinder Cube Equal for all the three Sphere ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Analogy between mass and heat transfer is not applicable in case of Same velocity profile or equal eddy diffusivities Viscous heating or chemical reaction Thermal or pressure mass diffusion Both B and C Same velocity profile or equal eddy diffusivities Viscous heating or chemical reaction Thermal or pressure mass diffusion Both B and C ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation. Increases Remains constant Decreases May increase or decrease ; depends on the material Increases Remains constant Decreases May increase or decrease ; depends on the material ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer Rate of heat transfer by vaporisation from pools of water is affected by the Surface tension of water Viscosity of water All of these Nature of heating surface and distribution of bubbles Surface tension of water Viscosity of water All of these Nature of heating surface and distribution of bubbles ANSWER DOWNLOAD EXAMIANS APP
Heat Transfer The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is 1.66 3.66 Dependent on NRe only 88.66 1.66 3.66 Dependent on NRe only 88.66 ANSWER DOWNLOAD EXAMIANS APP
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