Estimate the heat loss by natural convection from the surface of a heated horizontal cylindrical heater that has a surface temperature of 40°C and is immersed in water which is at a temperature of 26°C. From experiments , it is observed that the correlation Nu =0.53(GrPr)025 hold for all types of flow behavior. The properties of water at the mean temperature are : Density 994.9 kg/m2 Viscosity 7.65 kg/m s Specific heat 4.174 kJ/kg K Thermal conductivity 0.623 W/m K Coefficient if thermal expansion 3.26 x10 K

5. A laboratory water bath has an immersed horizontal (cylindrical) water element, 2.54 cm. in diameter and 35cm in length, with a power input of 500 W. If the bulk water temperature is 40 °C and heat transfer occurs by free convection only, calculate the surface temperature of the heater.

Transport Phenomena Question

Homework 2 The possible existence of an optimum insulation thickness for radial systems is suggested by the presence of competing effects associated with an increase in this thickness. In particular, although the conduction resistance increases with the addition of insulation, the convection resistance decreases due to increasing outer surface area. Hence there may exist an insulation thickness that minimizes heat loss by maximizing the total resistance to heat transfer. Resolve this issue by considering the following system. 1. A thin-walled copper tube of radius r, is used to transport a low-temperature refrigerant and is at a temperature Ti that is less than that of the ambient air at Ta around the tube. Is there an optimum thickness associated with application of insulation to the tube? 2. Confirm the above result by computing the total thermal resistance per unit length of tube for a 10-mm-diameter tube having the following insulation thicknesses: 0, 2, 5, 10, 20, and 40 mm. The…

Estimate the temperature gradient at the surface by convection over a surface of 4.6m2 area if the surface is at 232.3°C and fluid is at 46.6°C. The value of convective heat transfer coefficient is 5 W/m2.K. k=6.5W/mk.

Estimate the natural convection heat transfer coefficient of the horizontal pipe. The temperature of the outer surface of the pipe is 120 ° C. The ambient air temperature is 25 ° C. The outer diameter of the pipe is 10 cm. Convection coefficient = Answer W / m² ° C.

Heat is transferred from condensing steam to a vertical surface and the resistance to heat transfer is attributable to the thermal resistance of the condensate layer on the surface. For a film of liquid flowing down a vertical surface, the variables influencing the film thickness, include: viscosity of the liquid (water), density of the liquid, the volumetric flowrate per unit width of surface and the acceleration due to gravity. Obtain the relevant dimensionless groups. For streamline it is found that the film thickness is proportional to the one third power of the volumetric flowrate per unit width. Calculate the percent change in thickness if the gravity increase by one-third of its original value?

An uninsulated steam pipe passes through a room in which the air and walls are at 28°C. The outside diameter of the pipe is 70 mm, and its surface temperature and emissivity are 400°F and 0.80 respectively. If the coefficient associated with free convection heat transfer from 3.

Pls provide a complete and step by step solution. TY!

Draw flow diagrams for questions 2-4 and solve questions 1-4 with appropriate steps and correct values