There are many correlations for predicting boiling heat transfer coefficient. The correlation given by Foster and Zuber (1955) can be used to estimate pool nucleate boiling coefficients (h) in the absence of experimental data, as shown below. 0.79 0.45040 C Pi h =0.00122 (T.-T.) (p. - p.)* Estimate the heat-transfer coefficient for the pool cooling of water at 1.98 bar, from a surface at 125 °C. Check that the critical flux is not exceeded.

There are many correlations for predicting boiling heat transfer coefficient. The correlation given by Foster and Zuber (1955) can be used to estimate pool nucleate boiling coefficients (h) in the absence of experimental data, as shown below. 0.79 0.45040 C Pi h =0.00122 (T.-T.) (p. - p.)* Estimate the heat-transfer coefficient for the pool cooling of water at 1.98 bar, from a surface at 125 °C. Check that the critical flux is not exceeded.

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.21P

See similar textbooks

Similar questions

Water is to be boiled at atmospheric pressure in a polished copper pan by means of an electric heater. The diameter of the pan is 0.51 m and is kept at 111 deg C. What is the power required to boil the water? Tsat = 100°C; Properties of water at 100°C: Density, ρl= 961 kg/m3; Kinematic viscosity, ν = 0.293x10-6 m2/s; Prandtl Number, Pr = 1.740; Specific heat, Cpl = 4216 J/kg.K; Dynamic viscosity, μ = ρ × ν = 961 × 0.293 × 10-6 = 281.57 x10-6 Ns/m2; hfg = 2256.9 kJ/kg; ρv = 0.597 kg/m3; σ = 0.0588 N/m; Csf=0.013; n=1; Select one: a. 25964.0356 b. 52997.1101 c. 49373.4011 d. 38911.7986
Water is to be boiled at atmospheric pressure in a polished copper pan by means of an electric heater. The diameter of the pan is 0.48 m and is kept at 108 deg C. What is the power required to boil the water? Tsat 100°C; Properties of water at 100°C: Density. pl= 961 kg/m3; Kinematic viscosity, v 0.293x10-6 m2/s: Prandti Number. Pr 1.740; Specific heat, Cpl = 4216 J/kg.K; Dynamic viscosity, u = p x v = 961 x 0.293 x 10-6 = 281.57 x10-6 Ns/m2; hfg = 2256.9 k/kg; pv = 0.597 kg/m3; a = 0.0588 N/m; Csf=0.013; n=1:
Scale and sludge formation causes serious problems in boilers. Explain how the scalesand sludge are formed in the boilers and the problems caused by them. How can theseproblems be avoided?
Water is boiled at 250°F by a 2-ft-long and 0.5-in diameter nickel-plated electric heating element maintained at 280°F. Determine (a) the boiling heat transfer coefficient, (b) the electric power consumed by the heating element, and (c) the rate of evaporation of water.
Will the largest condensation heat transfer coefficient always be obtained for a horizontal finned tube with the maximum possible fpm?
6. A vertica platc 450 mm high and maintained at 3°C is exposed o satuated seam atatmospheric pressare. Calculte: (1) The rate of hea ransfe, and () The condensate a per hour per mete for plae widih film condensation. “The propertiesof waer im at the mean temperaure are: 0.3 kg/m sk = 6.4 x 10 WinC; = 434 x 10° kg/ms; and b = 22569 kg [Ans. 4399 x 10° kI, 2188 ke/h]
What do you mean by condensation? Explain in details.
Water in a tank is to be boiled at 143.27 Pa absolute pressure by a 1.5-cm-diameter brass heating element equipped with electrical resistance wires inside, as shown in the figure. Determine the maximum heat flux that can be attained in the nucleate boiling regime and the surface temperature of the heater in that case. (3.23x105 W/m2, 118.6°C)
Which of the following is not an assumption that Nusselt made in analytically deriving the average heat transfer coefficient over a vertical surface surrounded by vapor undergoing film condensation? A. Film thickness is zero at the top of surface B. Falling film is undergoing laminar flow C. Heat transfer from the condensing vapor to the surface is happening via natural convection D. All the assumptions above are important to the film condensation problem
In what kind of pot will a given volume of water boil at a higher temperature: a tall and narrow one or a short and wide one? Explain.
A horizontal pipe of 125-mm-diamter and 1 m long with a surface temperature of 95 ℃ is used to condense saturated steam at 1 atm. Determine the heat transfer rate for the condensation process. Properties of Water, vapor (1 atm): Tsat = 100℃, ρv = 0.596 kg/m3, hfg = 2257 kJ/kg; Water, liquid (Tf = 370K): ρl = 960.6 kg/m3, Cpl = 4214 J/kg.K, μl = 289*10^-6 N.s/m2, kl = 0.679 W/m.K.
Explain the concept of heat transfer, and spontaneity and probability base on the increasing temperature of gas molecules in the chamber.