Chapter 9, Problem 2CP

Define and explain the physical significance of the following:(a)prandtl number(b) Reynolds number (c)Nusselt number In which mode of heat transfer is the convection heat transfer coefficient usually higher, natural convection or force convection?why?

What are the key factors that influence the convective heat transfer coefficient in a mechanical system, and how can engineers optimize these factors to enhance heat transfer efficiency?

An average man has a body surface area of 1.8 m2  and a skin temperature of 330C. The convective heat transfer coefficient for a clothed person walking in still air is expressed as  h= 8.6V0.53 where V is the walking velocity in m/s. Assuming the average surface temperature of the clothed person to be 300C, determine the rate of heat lost by convection from an average man walking in still air at 100C at a walking velocity of 1.2 m/s.

Consider a person standing in a breezy room at 20°C. Determine the total rate of heat transfer from this person if the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29°C, respectively, and the convection heat transfer coefficient is 6 W/m2 ·°C (Fig. 2–75).

What regime favors heat transfer and why?Laminar, Turbulent or Transitional

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.

any relationship between inlet, outlet diameter and Effectiveness in heat transfer? How outlet and inlet diameter effects on Effectiveness?

An average man has abody surface area of 1.8m2 and a skin temperature of 33degrees celcius .The convection heat transfer coefficient for a clothed person walking in still air is expressed as {h,8.6V^0.53}FOR 0.5<v<2m/s,where V is the walking velocityin m/s.Assuming the average surface temperature of the clothed person to be 30degrees celcius, determine the rate of heat loss from an average man walking in still air at 10degrees celcius by convectionat a walking velocity of  (a)0.5m/s (b)1.0m/s (c)1.5m/s (d)2.0m/s

For heat transfer purposes, a standing man can be modeled as a 30-cm-diameter, 175-cm-long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34°C. For a convection heat transfer coefficient of 10 W/m2 ·°C, determine the rate of heat loss from this man by convection in an environment at 20°C.