Consider the packed bed of aluminum spheres described in Problem 5.12 under conditions for which the bed is charged by hot air with an inlet velocity of
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Fundamentals of Heat and Mass Transfer
- 2. Calculate the free convection heat transfer coefficient for a plate 6 ft high and 8 ft wide at 120 °F that is exposed to nitrogen at 60 °F. (see attached) 3. Constant Flux Application. Air at 1 atm and 300 °C is cooled as it flows at a velocity of 5.0 m/s through a tube with a diameter of 2.54 cm. Calculate the heat transfer coefficient if a constant heat flux condition is maintained at the wall and the wall temperature is 20 °C above the temperature along the entire length of the tube. (See attached)arrow_forwardThe pressure is 101.32 kPa and the air velocity at 316.5 k is 0.61m / s. The surface of the sphere is 277.76 k and its average diameter is 114 mm. Calculate the heat transfer coefficient for the air blown aroundarrow_forwardSolve it ASAParrow_forward
- I need the answer as soon as possiblearrow_forwardThe cake mix, whose initial temperature is 25C, will be baked at 120C in a cylindrical mold. It takes 802 h for the core temperature of the cake to reach 98C and this time is considered sufficient for baking the cake. Calculate the diameter of the mold in which the cake should be placed. h = 68.6 W / m2K, d = 840 kg / m3 cp = 3400 J / kgK, k = 1.2 W / mK, λ = 3.07arrow_forwardIt is aimed to produce frozen potatoes in a newly established business. The entry temperature of the cleaned potato to the system is -16 °C, and the desired temperature to reach 10 °C. For this purpose, a refrigerant at -25 °C will be used. In the freezing process, potatoes of certain sizes are placed in the ice cream basket, the basket is immersed in the tank containing the refrigerant and kept during freezing. A cooling system is designed around the tank and 1M Joule per hour removes heat from the tank to keep the temperature of the tank constant at -25 °C. It is desirable to produce potatoes of different shapes. These shapes are spheres with a diameter of 20 mm, a cube with dimensions of 16x16x16 mm and a rectangular prism with a diameter of 12x12x25 mm. In such a process,a. What should be used as refrigerant?b. What is the daily production capacity for each product?c. What would you recommend to increase production capacity?arrow_forward
- A thermocouple junction, which may be approximated as a sphere, is to be used for temperature measurement in a gas stream. The convection coefficient between the junction surface and the gas is h=400W/m².K, and the junction thermophysical properties are ĸ= 20W/m.°K, c= 400J/kg.°K and ρ=8500kg/m³. Determine the junction diameter needed for the thermocouple to have a time constant of 1s. If the junction is at 25°C and is placed in a gas stream that is at 200°C, how long will it take for the junction to reach 199°C?arrow_forwardExperiments have been conducted on a metallic cylinder 12.7 mm in diameter and 94 mm long. The cylinder is heated internally by an electrical heater and is subjected to a cross flow of air in a low-speed wind tunnel. Under a specific set of operating conditions for which the upstream air velocity and temperature were maintained at V = 10 m/s and 26.2°C, respectively, the heater power dissipation was measured to be P = 46 W, while the average cylinder surface temperature was determined to be T, = 128.4°C. It is estimated that 15% of the power dissipation is lost through the cumulative effect of surface radiation and conduction through the endpieces. Thermocouple for measuring airstream temperature Pitot tube for determining velocity Wind tunnel Power leads to electrical heater Heated cylinder Insulated endpiece Thermocouple leads 1. Determine the convection heat transfer coefficient from the experimental observations. 2. Compare the experimental result with the convection coefficient…arrow_forwardQuestion 4: Consider a sphere with a diameter of 25 mm and a surface temperature of 60°C that is immersed in a fluid at a temperature of 30°C and a velocity of 2 m/s. Calculate the drag force and the heat rate when the fluid is (a) water and (b) air at atmospheric pressure. Explain why the results for the two fluids are so different.arrow_forward
- In the final stages of production, a pharmaceuticalis sterilized by heating it from 30°C to 75°C as it moves at0.2 m/s through a straight thin-walled stainless steeltube of 12.7-mm diameter. A uniform heat flux is maintained by an electric resistance heater wrappedaround the outer surface of the tube. If the tube is 10 m long, what is the required heat flux? If fluidenters the tube with a fully developed velocity profile and a uniform temperature profile, what is thesurface temperature at the tube exit? Fluid properties may be approximated as ? = 1000 kg/m3, cp =4000 J/kg K, ? = 2 x 10-3 kg/s m, k = 0.8 W/m K, and Pr = 10.arrow_forwardQ6: A large vertical plate 6.1 m high and 1.22 m wide is maintained at s constant temperature of 57:C and exposed to atmospheric air at 4-C. Caleulate the heat lost by the plate. Answers: Qarrow_forwardHeat transfer. Show all steps for solutionarrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning