Chap 13 Heat Exchangers
The Effectiveness-NTU Method 13-68C When the heat transfer surface area A of the heat exchanger is known, but the outlet temperatures are not, the effectiveness-NTU method is definitely preferred. 13-69C The effectiveness of a heat
Chapter 15 Cooling of Electronic Equipment 15-140 A multilayer circuit board consisting of four layers of copper and three layers of glass-epoxy sandwiched together is considered. The magnitude and location of the maximum temperature that occurs in the PC
Chapter 14 Mass Transfer 14-134 A circular pan filled with water is cooled naturally. The rate of evaporation of water, the rate of heat transfer by natural convection, and the rate of heat supply to the water needed to maintain its temperature constant a
Preface
This manual is prepared as an aide to the instructors in correcting homework assignments, but it can also be used as a source of additional example problems for use in the classroom. With this in mind, all solutions are prepared in full detail in
Chapter 14 Mass Transfer 14-119 A person is standing outdoors in windy weather. The rates of heat loss from the head by radiation, forced convection, and evaporation are to be determined for the cases of the head being wet and dry. Assumptions 1 The low m
Chapter 2 Heat Conduction Equation
Variable Thermal Conductivity
2-94C During steady one-dimensional heat conduction in a plane wall, long cylinder, and sphere with
constant thermal conductivity and no heat generation, the temperature in only the plane wa
Chapter 2 Heat Conduction Equation
2-126 A spherical liquid nitrogen container is subjected to specified temperature on the inner surface
and convection on the outer surface. The mathematical formulation, the variation of temperature, and
the rate of evap
Chapter 2 Heat Conduction Equation
Solution of Steady One-Dimensional Heat Conduction Problems
2-52C Yes, this claim is reasonable since in the absence of any heat generation the rate of heat transfer through a plain wall in steady operation must be const
Chapter 15 Cooling of Electronic Equipment
Air Cooling: Forced Convection 15-94C Radiation heat transfer in forced air cooled systems is usually disregarded with no significant error since the forced convection heat transfer coefficient is usually much la
Chapter 3 Steady Heat Conduction
Chapter 3
STEADY HEAT CONDUCTION
Steady Heat Conduction In Plane Walls
3-1C (a) If the lateral surfaces of the rod are insulated, the heat transfer surface area of the cylindrical
rod is the bottom or the top surface area
Chapter 15 Cooling of Electronic Equipment
Chapter 15 COOLING OF ELECTRONIC EQUIPMENT
Introduction and History 15-1C The invention of vacuum diode started the electronic age. The invention of the transistor marked the beginning of a revolution in that age
Chapter 15 Cooling of Electronic Equipment Air Cooling: Natural Convection and Radiation 15-71C As the student watches the movie, the temperature of the electronic components in the VCR will keep increasing because of the blocked air passages. The VCR eve
Chap 15 Heat Exchangers 13-54 Glycerin is heated by ethylene glycol in a thin-walled double-pipe parallel-flow heat exchanger. The rate of heat transfer, the outlet temperature of the glycerin, and the mass flow rate of the ethylene glycol are to be deter
Chap 13 Heat Exchangers
Chapter 13 HEAT EXCHANGERS
Types of Heat Exchangers 13-1C Heat exchangers are classified according to the flow type as parallel flow, counter flow, and crossflow arrangement. In parallel flow, both the hot and cold fluids enter the
Chap 15 Heat Exchangers
The Log Mean Temperature Difference Method 13-32C Tlm is called the log mean temperature difference, and is expressed as Tlm = where T1 = Th,in - Tc ,in T = Th ,in - Tc,out T2 = Th ,out - Tc,out T2 = Th ,out - Tc,in for parallel-fl
Chapter 14 Mass Transfer
Diffusion in a Moving Medium 14-74C The mass-average velocity of a medium at some location is the average velocity of the mass at that location relative to an external reference point. It is the velocity that would be measured by
Chapter 14 Mass Transfer
Chapter 14 MASS TRANSFER
Mass Transfer and Analogy Between Heat and Mass Transfer 14-1C Bulk fluid flow refers to the transportation of a fluid on a macroscopic level from one location to another in a flow section by a mover such
Chapter 14 Mass Transfer 14-107 A raindrop is falling freely in atmospheric air. The terminal velocity of the raindrop at which the drag force equals the weight of the drop and the average mass transfer coefficient are to be determined. Assumptions 1 The
Chapter 14 Mass Transfer
Steady Mass Diffusion Through a Wall 14-42C The relations for steady one-dimensional heat conduction and mass diffusion through a plane wall are expressed as follows: Heat conduction: Mass diffusion: T -T Qcond = - k A 1 2 L mdiff
Chap 13 Heat Exchangers
Review Problems 13-111 Hot oil is cooled by water in a multi-pass shell-and-tube heat exchanger. The overall heat transfer coefficient based on the inner surface is to be determined. Assumptions 1 Water flow is fully developed. 2 P
Chapter 15 Cooling of Electronic Equipment 15-55 A plastic DIP with 16 leads is cooled by forced air. Using data supplied by the manufacturer, the junction temperature is to be determined. Assumptions Steady operating conditions exist. Analysis The juncti
Chapter 2 Heat Conduction Equation
2-68 A compressed air pipe is subjected to uniform heat flux on the outer surface and convection on the
inner surface. The mathematical formulation, the variation of temperature in the pipe, and the surface
temperatures
Chapter 2 Heat Conduction Equation
Chapter 2
HEAT CONDUCTION EQUATION
Introduction
2-1C Heat transfer is a vector quantity since it has direction as well as magnitude. Therefore, we must
specify both direction and magnitude in order to describe heat trans
Chapter 1 Basics of Heat Transfer
Heat Transfer Mechanisms
1-44C The thermal conductivity of a material is the rate of heat transfer through a unit thickness of the
material per unit area and per unit temperature difference. The thermal conductivity of a
Chapter 6 Fundamentals of Convection
6-39 The oil in a journal bearing is considered. The velocity and temperature distributions, the maximum temperature, the rate of heat
transfer, and the mechanical power wasted in oil are to be determined.
Assumptions
Chapter 7 External Forced Convection
7-39 A steam pipe is exposed to windy air. The rate of heat loss from the steam is to be determined.
Assumptions 1 Steady operating conditions exist. 2 Radiation effects are negligible. 3 Air is an ideal gas with const
Chapter 7 External Forced Convection
7-52 A steam pipe is exposed to a light winds in the atmosphere. The amount of heat loss from the steam during a certain period and
the money the facility will save a year as a result of insulating the steam pipe are t
Chapter 7 External Forced Convection
7-63
Chapter 7 External Forced Convection
Review Problems
7-90 Wind is blowing parallel to the walls of a house. The rate of heat loss from the wall is to be determined.
Assumptions 1 Steady operating conditions exist.
Chapter 7 External Forced Convection
7-99 Wind is blowing over the roof of a house. The rate of heat transfer through the roof and the cost of this heat loss for 14-h period
are to be determined.
Assumptions 1 Steady operating conditions exist. 2 The crit
Chapter 7 External Forced Convection
7-14 Hot engine oil flows over a flat plate. The total drag force and the rate of heat transfer per unit width of the plate are to be
determined.
Assumptions 1 Steady operating conditions exist. 2 The critical Reynolds