Air at 1 atm and 20°C is flowing over the top surface of a 0.2 m x 0.5 m-thin metal foil. The air stream velocity is 100 m/s and the metal foil is heated electrically with a uniform heat flux of 6100 W/m2. If the friction force on the metal foil surface is 0.3 N, determine the surface temperature of the metal foil. Evaluate the fluid properties at 100°C.

Fruit is impeded from ripening when it reaches high temperatures (>32°C). Farmer Joe isworried that Deleware's summer heat wave will affect the ripening of his ground cherries.The spherical fruit (1 cm in diameter) is surrounded by a spherical papery husk (λhusk = 0.3W/m K) with an inner diameter of 2 cm and an outer diameter of 2.1 cm. The air in betweenthe fruit and the husk is stagnant (λair = 0.03 W/m K). On a calm day in July, the delewareair (outside of the husk) is very warm, with a temperature of ~38°C and a heat transfercoefficient of h deleware,calm = 10 W/m 2K. (a) Sketch the system, labeling all temperatures, dimensions, and proportionality constants. (b) sketch the electrical analogy tothis system, labeling all temperatures, resistances, and heat flows (c) what is the overall resistance to heat transfer from the air in Deleware to the fruit?

2. Consider airflow over a plate surface maintained at a temperature of 215°C. The temperature profile of the airflow is given as T(y) = Too (Too - T,) exp (- V fluid The airflow at 1 atm has a free stream velocity and temperature of 5 cm/s and 25°C, respectively. Determine the heat flux on the plate surface and the convection heat transfer coefficient of the airflow.

A fluid with a constant density of 961 kg/m3 and a constant viscosity of 1.419×10-3 Kg/m.s is flowing over a flat plate at a stream free velocity of 0.87 m/s. If the plate has a length of 2 m, answer the following: 1.What is Reynolds number at a point that is (1/4)L down the entrance?  2.Is the flow laminar or turbulent? 3.Calculate the thickness of the boundary layer in mm at (1/4)L down the entrance 4.Calculate the drag coefficient at (1/4)L down the entrance

Air is to be heated by passing it over a bank of 4-m-long tubes inside which steam is condensing at 100°C. Air approaches the tube bank in the normal direction at 20°C and 1 atm with a mean velocity of 5.2 m/s. The outer diameter of the tubes is 0.016 m, and the tubes are arranged staggered with longitudinal and transverse pitches of SL = ST = 0.03 m. There are 20 rows in the flow direction with 10 tubes in each row. Assume the air properties at mean temperature of 35°C and 1 atm. The air properties at the assumed mean temperature of 35°C and 1 atm are k = 0.02625 W/m·K, ρ = 1.145 kg/m3, cp = 1.007 kJ/kg·K, Pr = 0.7268, μ = 1.895 × 10−5 kg/m·s, Prs = Pr@Ts = 100°C = 0.7111.   Determine the pressure drop across the tube bank