Question 41. For turbulent flow over a flat plate, the average value of Nusselt number is prescribed by the relation
Nu = 0.664 (Re)^0.5 (Pr)^0.33
Which of the following is then a false statement?
The average heat transfer coefficient increases as

Question 42. A thin walled duct of 0.5 m diameter has been laid in an atmosphere of quiescent air at 15 degree Celsius and conveys a particular gas at 205 degree Celsius. Base your calculations on one meter length of the duct, estimate the convective coefficient of heat transfer

Question 43. A nuclear reactor with its core constructed of parallel vertical plates 2.25 m high and 1.5 m wide has been designed on free convection heating of liquid bismuth. Metallurgical considerations limit the maximum surface temperature of the plate to 975 degree Celsius and the lowest allowable temperature of bismuth is 325 degree Celsius. Estimate the maximum possible heat dissipation from both sides of each plate. The appropriate correlation for the convection coefficient is
Nu = 0.13 (Gr Pr)^1/3

Question 44. The free convection coefficient is given by
h = C₁ d t m/l^(1 – 3m)
The value of exponent for laminar flow is

Question 45. Free correction modulus is given by

Question 46. Which of the following is true for turbulent flow?

Question 47. Calculate the rate of heat loss from a human body which may be considered as a vertical cylinder 30 cm in diameter, and 175 cm high while standing in a 30 km/hr wind at 15 degree Celsius. Human has a surface temperature of 35 degree Celsius

Question 48. Investigate the effect of following condition on the average value of heat transfer coefficient in flow through a tube
Two fold increases in flow velocity by varying mass flow rate
It may be presumed that there is no change in the temperature of the liquid and the tube wall, and that the flow through the tube is turbulent in character

Question 49. A heat treat steel plate measures 3 m by 1 m and is initially at 30 degree Celsius. It is cooled by blowing air parallel to 1 m edge at 9 km/hr. If the air is at 10 degree Celsius. Estimate the convection heat transfer from both sides of the plate

Question 50. Mc Adam relation is given by