Acomposite wall consists of 20 mm thick steel plate backed by insulation brick (k = 0.39 w/mk) of 50 cm thickness and overlaid by mineral wool of 20 cm thickness (k = 0.05 w/mk) and 70 cm layer of brick of (k = 0.39 w/mk). the inside is exposed to convection at 650°c with h = 65 w/ m2k. the outside is exposed to air at 35°c with a convection coefficient of 15 w/m2k. determine the heat loss per unit area, interface temperatures and temperature gradients in each materials.

Air is compressed isentropically from an initial state of 300 k and 101 kpa to a final temperature of 1000 k. determine the final pressure using the following approaches: (a) approximate analysis (using properties at the average temperature) (b) exact analysis

Abrayton cycle operates with a regenerator on the air-standard with properties evaluated at 400 k. the tem- perature of the air entering the compressor is 350k while the temperature of the air exiting the compressor is 600 k. the temperature of the air entering the turbine is 1600 k. the overall cycle produced 600 kj/kg of net work out. assuming a regenerator effectiveness of 0.8, what is the temperature of the air before heat addition (combustion)? draw this process on a t - s diagram

Steam in a heating system flows through tubes whose outer radius is 2.5 cm and whose walls are maintained at a temperature of 180 °c . circular aluminum alloy 2024-t6 fins ( k= 186 wm. k) of outer radius 3 cm and constant thickness 1 mm are attached to the tube. the space between the fins is 3 mm and thus there are 250 fins per meter of tube length. heat is transferred to the surrounding air at too-25 °c, with a heat transfer coefficient of 40 w/m2. k. manufacturer a claims that this system is rated at 3.5 kw per meter of tube length. if the fins are an integral part of the steam tube, find the heat transfer rate in kw for a 1-m length of tube. is manufacturer a's claim valid? compare the heat transfer rate from 1 meter of tube length if there are no fins.