(b) Stainless steel ball bearings (p = 8085 kg/m³ and cp= 0.480 kJ/kg°C) having a diameter of 1.22 cm are to be quenched in water at a rate of 1402 per minute. The balls leave the oven at a uniform temperature of 900°C and are exposed air at 30°C for a while before they are dropped into the water. If thetemperature of the balls drops to 855°C prior to quenching, determine: (i) The rate of heat transfer from the balls to the air; and (ii) The rate of entropy generation due to heat loss from the balls to the air.

(b) Stainless steel ball bearings (p = 8085 kg/m³ and cp= 0.480 kJ/kg°C) having a diameter of 1.22 cm are to be quenched in water at a rate of 1402 per minute. The balls leave the oven at a uniform temperature of 900°C and are exposed air at 30°C for a while before they are dropped into the water. If thetemperature of the balls drops to 855°C prior to quenching, determine: (i) The rate of heat transfer from the balls to the air; and (ii) The rate of entropy generation due to heat loss from the balls to the air.

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.

Chapter8: Natural Convection

Section: Chapter Questions

Problem 8.3P

See similar textbooks

Similar questions

) Stainless steel ball bearings (ρ = 8085 kg/m3and cp = 0.480 kJ/kgC) having adiameter of 1.22 cm are to be quenched in water at a rate of 1402 per minute.The balls leave the oven at a uniform temperature of 900C and are exposed to air at 300C for a while before they are dropped into the water. If thetemperature of the balls drops to 855C prior to quenching, determine:(i) The rate of heat transfer from the balls to the air; and(ii) The rate of entropy generation due to heat loss from the balls to the air.
Example 7 A cooking pan whose inner diameter is 20 cm is filled with water and covered with a 4-kg lid. If the local atmospheric pressure is 101 kPa, determine the temperature at which the water starts boiling when it is heated. Answer: 100.2°C Patm = 101 kPa mlid = 4 kg H,0
A total of 250 g of CO2 gas at 373 K is heated to 773 K at a pressure of 101.32 kPa. Calculate the amount of heat needed in: a. Answercal b. Answerbtu c. AnswerkJ
Calculate delta S when 1 mole of supercooled water at –10oC and 100 kPa is converted into ice at -10oC and 100 kPa. The molar heat capacity at constant pressure (Cm,P) of ice is 37.7 J K-1 mol- 1, and that of supercooled water is 76.1 J K-1 mol-1. The enthalpy of freezing of water is -6004 J mol-1. final answer: -20.54 J K-1
If 10kg of water at 920kPa pressure and at 600C is heated to boiling point, then to dry saturated steam and then to superheated steam at a temperature of 2100C, determine: The sensible heat and latent heat
Four cubic meters of water is to be heated by means of four 1.5 kW, 230-V immersion heating elements. Assuming the efficiency of the heater as 90%, determine the time required in boiling the water if the initial temperature is 20°C and if the elements are connected two in series in parallel with two in series. the answer is 275.6 hrs (According to the ECE board exam answer key) can you show me the solution?
Complete this table for refrigerant-134a:
The normal boiling point of copper is 2845 K and its molar enthalpy of vvaporization is 300.3 kj/mol. What is the change in the entropy in the system when 127 g of copper vapor condenses to liquid at the normal boiling point? MW=63.5
Steam of 1.4MN/m2 and of dryness fraction 0.7 is throttled to 0.11MN/m2 determine the dryness fraction of the steam after throttling?
A tank containing 100 kg of water. copper tube wound in a coil with 4.0 m length of 15 mm-O.D, 2 mm-wall-thickness, The tank contains a stirrer driven by a small electric motor, and the walls of the tank are well insulated. If the initial temperature of the water is 20°C, A stream of 1 g/s of hydrogen gas at 1 MPa and 80°C is to be cooled, the H2 gas is passed through the coil, will the outlet temperature be less than 28°C after 2 hours of operation?
A 10 kg copper block (specific heat .=0.4 kJ/ Kg) at 90degC is immersed into an insulated tank containing 0.35m^3 of water at 30 degreesC. Applying first law, calculate equilibrium temperature.
Determine the quantity (volume) of saline water in a steam generator. The heat energy of 1738 kJ is supplied to saline water in the steam generator to heat from 26ºC to 111ºC for the generation of water vapor, Take the density & specific heat of the solution as 1031 kg/m3 & 3.6 J/kgºK respectively. Solution: Change in Temperature (in K) Answer for part 1 Mass of the saltwater (in kg) Answer for part 2 Quantity (Volume) of saltwater (in m3) Answer for part 3