KNOWN: Thermal conductivity, thickness and temperature difference across a sheet of rigid
FIND: (a) The heat flux through a 2 m 2 m sheet of the insulation, and (b) The heat rate
through the sheet.
A = 4 m2
KNOWN: Thermal conductivities and thicknesses of original wall, insulation layer, and glass layer.
Interior and exterior air temperatures and convection heat transfer coefficients.
FIND: Heat flux through original and retrofitted walls.
KNOWN: Dimensions and properties of a composite wall exposed to convective or insulated
FIND: (a) Maximum wall temperature for left face insulated and right face convectively cooled,
(b) Sketch the steady-state temperature distrib
KNOWN: Temperature and velocity of water flow in a pipe of prescribed dimensions.
FIND: Pressure drop and pump power requirement for (a) a smooth pipe, (b) a cast iron pipe with a clean
surface, and (c) smooth pipe for a range of mean velociti
KNOWN: Electric heater at bottom of tank of 400mm diameter maintains surface at 70C
with engine oil at 5C.
FIND: Power required to maintain 70C surface temperature.
ASSUMPTIONS: (1) Oil is quiescent, (2) Quasi-steady state conditio
KNOWN: Dimensions and surface temperature of electrically heated strips. Temperature and velocity
of air in parallel flow.
FIND: (a) Rate of convection heat transfer from first, fifth and tenth strips as well as from all the strips,
(b) For ai