Layers of 23-cm-thick meat slabs
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Heat And Mass Transfer (asia Higher Education Engineering/computer Science Mechanica)
- A cylindrical fuel rod of 2 cm in diameter is encased in a concentric tube and cooled by water. The fuel generates heat uniformly at a rate of 150 MW/m3. The convection heat transfer coefficient on the fuel rod is 5000 W/m2∙K, and the average temperature of the cooling water, sufficiently far from the fuel rod, is 70°C. Determine the surface temperature of the fuel rod and discuss whether the value of the given convection heat transfer coefficient on the fuel rod is reasonable.arrow_forwardIn the effort to find the best way to cool a smooth thin-walled copper tube, an engineer decided to flow air either through the tube or across the outer tube surface. The tube has a diameter of 6 cm, and the surface temperature is maintained constant. Determine the convection heat transfer coefficient when air is flowing through a thin-walled tube at 25 m/s with bulk mean temperature of 50°C. _____ w/m^2karrow_forwardWater is to be heated from 10°C to 80°C as it flows through a 2-cm-internal-diameter, 13-m-long tube. The tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. If the system is to provide hot water at a rate of 5 L/min, determine the power rating of the resistance heater. Also, estimate the inner surface temperature of the pipe at the exit.arrow_forward
- A heating system is to be designed to keep the wings of an aircraft cruising at a veloeity of 900 km/h above freezing temperatures during flight at 12.200-m altitude where the standard atmospheric conditions are -55.4°C and 188 kPa. Approximating the wing as a cylinder of elliptical cross section whose minor axis is 30 cm and disregarding radiation, determine the average convection heat transfer coefficient on the wing surface and the average rate of heat transfer per unit surface area.arrow_forwardA 40-cm-long, 800-W electric resistance heating element with diameter 0.5 cm and surface temperature 120°C is immersed in 75 kg of water initially at 20°C. Determine how long it will take for this heater to raise the water temperature to 80°C. Also, determine the convection heat transfer coefficients at the beginning and at the end of the heating process.arrow_forwardCombustion gases passing through a 3-cminternal- diameter circular tube are used to vaporize waste water at atmospheric pressure. Hot gases enter the tube at 115 kPa and 250°C at a mean velocity of 5 m/s, and leave at 150°C. If the average heat transfer coefficient is 120 W/m2?K and the inner surface temperature of the tube is 110°C, determine (a) the tube length and (b) the rate of evaporation of water.arrow_forward
- What regime favors heat transfer and why?Laminar, Turbulent or Transitionalarrow_forwardLayers of 23 cm-thick meat slabs ( k = 0.47 W/m*C and a=0.13*10 m/s) initially at a uniform temperature of 7 C are to be frozen by refrigerated air at -30 C flowing at a velocity of 1.4 m/s. the average heat transfer coefficient between the meat and the air is 20 W/m*C. Assuming the size of meat slabs to be large relative to their thickness, determine how long it will take for the center temperature of the slabs to drop to -18 C, Also, determine the surface temperature of the meat slab at that timearrow_forwardEngine oil at 54oC54oC flows over the upper surface of a 5m5m long plate whose temperature is 20oC20oC with a velocity of 2m/s2m/s. What is the heat transfer rate per unit width of the plate?arrow_forward
- Air enters a 20-cm-diameter 12-m-long underwater duct at 50°C and 1 atm at a mean velocity of 7 m/s, and is cooled by the water outside. If the average heat transfer coefficient is 85 W/m2 °C and the tube temperature is nearly equal to the water temperature of 5°C, determine the exit temperature of air and the rate of heat transferarrow_forwardConsider turbulent forced convection in a circular tube. Will the heat flux be higher near the inlet of the tube or near the exit? Why?arrow_forwardConsider water (at a temperature of 276 K ) flowing inside a cylindrical pipe, having a diameter of 0.1 m and a thin wall. Under specific circumstances, temperature at the wall of the pipe reaches 258 K that helps form a layer of ice on the inner side of the wall of the pipe. Temperature and convection heat transfer coefficient at the inner surface of the ice layer are 273 K and 1500m2⋅Kw, respectively. Determine how thick the ice layer should be?arrow_forward
- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning