10. Air is to be cooled and dehumidified by counter-current contact with water in a packed tower. The tower is to be designed for the following conditions, DBT and WBT are 28'C and 25°C respectively. Flow rate of inlet air 700 kg hof dry air. Inlet and outlet temperatures of water are 10'C and 18'C respectively. For the entering air estimate (i) humidity (ii) %R.H (i1) Dewpoint and (iv) enthalpy. 4/4 (Ans: ) 0.019 kgkg. (ii) 88.08%, (iHi) 23.5°C and(iv) 79.22 kJkg dry

In a certain manufacturing process a certain Liquid gas under 14.7 psia pressure with has a normal boiling point of -183 °C. They decided to be store this in a spherical container with 11.811 inches OD. The system is kept adiabatic by enclosing the container inside another concentric sphere of 0.45 m ID, with intervening space evacuated. Both the sphere surfaces are made of aluminum with e= 0.3. The temperature of the outer sphere is 40°C. To miminized heat gain a polished aluminum with an emissivity of 0.03 was used for container walls. Determine the percentage reduction.choices 81,90% 10.67% 83.12% 39,68% 78.56% 89.75%

1. Liquid oxygen is stored in a spherical tank with D = 5 ft. The surface of the tank was isolated with insulation material A with a thickness of 8 in and outside with material B with a thickness of 0.5 ft (kA = 0.022 Btu / j.ft.oF and kB = 0.04 Btu / j.ft.oF). Tank surface temperature (–4) oC and insulation surface temperature 50oC Calculate heat transfer from air to liquid oxygen tank! 2. A 2.0 inch Schedule 40 pipe has k = 27 Btu / h.ft.oF. The fluid in the pipe has h = 30 Btu / h.ft2.oF. The outer surface of the pipe is coated with a fiber glass insulation thickness of 4 mm with k = 0.023 Btu / h.ft.oF. The convection coefficient on the outer surface of the insulation is 2.0 Btu / h.ft2.oF. The temperature of the fluid contained in the pipe is 320oF and the ambient temperature is 70oF. Calculate the heat loss per unit length of pipe! 3. Two parallel plates with a diameter of 60 cm, separated at a distance of 15 cm. The temperature on the top surface is 4 oC and the temperature on…