A chemically reacting mixture is stored in a thin-walled
spherical container of radius r1  200 mm, and the exothermic reaction generates heat at a uniform, but temperature dependent volumetric rate of 

o exp(A/To), where 
o  5000 W/m3

A 75 K, and To is the mixture temperature in kelvins. The vessel is enclosed by an insulating material of outer radius r2, thermal conductivity k, and emissivity. The outer surface of the insulation experiences convection heat transfer and net radiation exchange with the adjoining air and large surroundings, respectively.

 A 2 cm diameter glass rd (k = 0.8 W/mK) is 6 cm long. It has base temperature at 120ºC 
and is exposed to air at 20ºC. The temperature at the tip of the rod is measured as 35ºC. 
What is the convection heat transfer coefficient? How much heat is lost by the rod?

A piston–cylinder assembly contains air modeled
as an ideal gas with a constant specific heat ratio, k =
1.4. The air undergoes a power cycle consisting of
four processes in series: Process 1–2: Constanttemperature expansion at 600 K from p1 = 0.5 MPa to
p2 = 0.4 MPa. Process 2–3: Polytropic expansion with
n = 1.35 to p3 = 0.3 MPa. Process 3–4: Constantpressure compression to V4 = V1. Process 4–1:
Constant-volume heating. Determine (a) the work and
heat transfer for each process, in kJ/kg, and (b) the
thermal efficiency.