Homework 6 Solution (ChE 306, 2012)
KNOWN: Parallel flow over a flat plate and two locations representing a short span
x1 to x2 where (x2 - x1) < L.
FIND: Three different expressions for the average heat transfer coefficient over the
Homework-5 Solution (ChE306, 2012)
KNOWN: Form of the velocity and temperature profiles for flow over a surface.
FIND: Expressions for the friction and convection coefficients.
ANALYSIS: The shear stress at the wall is
KNOWN: Dimensions, thermal conductivity and surface temperatures of a concrete
slab. Efficiency of gas furnace and cost of natural gas.
FIND: Daily cost of heat loss.
ASSUMPTIONS: (1) Steady state, (2) One-dimensional conduction, (3
Homework-8 Solutions (2012)
KNOWN: Operating conditions and surface area of a finned-tube, cross-flow exchanger.
FIND: Overall heat transfer coefficient.
ASSUMPTIONS: (1) Negligible heat loss to surroundings, (2) Constant propertie
ChE 306 HW-3 Solution (2012)
KNOWN: Boundary conditions on four sides of a rectangular plate.
FIND: Temperature distribution.
ANALYSIS: This problem differs from the one solved in Section 4.2 only in the boundary
condition at the to
Exam-1 (Open Book, Open Notes)
ChE 306, Fall 2012 (Chem. Eng. Dept., NMSU)
1. An electric resistance heater is embedded in a long cylinder of diameter 30 mm.
When water with a temperature of 25 C and velocity of 1 m/s fl
Solution to HW-2
KNOWN: Curing of a transparent film by radiant heating with substrate and film
surface subjected to known thermal conditions.
FIND: (a) Thermal circuit for this situation, (b) Radiant heat flux, q o (W/m2), to
KNOWN: Conditions of the exhaust gas passing over a catalytic surface for the removal of NO.
FIND: (a) Mole fraction of NO at the catalytic surface, (b) NO removal rate.
ASSUMPTIONS: (1) Steady-state conditions, (2) One-dimensiona
Homework-9 Solutions (2012)
KNOWN: Partial pressures and temperature for a mixture of CO2 and N2.
FIND: Molar concentration, mass density, mole fraction and mass fraction of each
ASSUMPTIONS: (1) Perfect gas behavior.
Homework-4 Solution (ChE 306, 2012)
KNOWN: Electrical heater attached to backside of plate while front surface is
exposed to convection process ( ,h); initially plate is at a uniform temperature of the
ambient air and suddenly heater power i