Modern Engineering Thermodynamics

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Preface
TEXT FEATURES
1. Style. To make the subject as understandable as possible, the writing is somewhat conversational and the
importance of the subject is evidenced in the enthusiasm of the presentation. The composition of the
engineering student body has been changing in recent years, and it is no longer assumed that the students
are all men and that they inherently understand how technologies (e.g., engines) operate. Consequently, the
operation of basic technologies is explained in the text along with the relevant thermodynamic material.
2. Significant figures. One of the unique features of this text is the treatment of significant figures. Professors
often lament about the number of figures provided by students on their homework and examinations. The
rules for determining the correct number of significant figures are introduced in Chapter 1 and are followed
consistently throughout the text. An example from Chapter 1 follows.
EXAMPLE 1.6
The inside diameter of a circular water pipe is measured with a ruler to two significant figures and is found to be 2.5 inches.
Determine the cross-sectional area of the pipe to the correct number of significant figures.
Solution
The cross-sectional area of a circle is A = πD 2 /4, so A pipe = π(2.5 inches) 2 /4 = 4.9087 in 2 , which must be rounded to 4.9 in 2 ,
since the least accurate value in this calculation is the pipe diameter (2.5 inches), which has only two significant figures.
3. Chapter overviews. Each chapter begins with an overview of the material contained in the chapter.
4. Problem-solving strategy. A proven technique for solving thermodynamic problems is discussed early in the
text and followed throughout in the solved examples. The technique follows these steps:
SUMMARY OF THE THERMODYNAMIC PROBLEM-
SOLVING TECHNIQUE
Begin by carefully reading the problem statement completely through.
Step 1. Make a sketch of the system and put a dashed line around the system boundary.
Step 2. Identify the unknown(s) and write them on your system sketch.
Step 3. Identify the type of system (closed or open) you have.
Step 4. Identify the process that connects the states or stations.
Step 5. Write down the basic thermodynamic equations and any useful auxiliary equations.
Step 6. Algebraically solve for the unknown(s).
Step 7. Calculate the value(s) of the unknown(s).
Step 8. Check all algebra, calculations, and units.
Sketch → Unknowns → System → Process → Equations → Solve → Calculate → Check
5. Solved example problems. Over 200 solved example problems are provided in the text. These examples
were carefully designed to illustrate the preceding text material. A sample from Chapter 5 follows.
EXAMPLE P.1
Read the problem statement. An incandescent lightbulb is a simple electrical device. Using the energy rate balance on a
lightbulb, determine the heat transfer rate of a 100. W incandescent lightbulb.
Solution
Step 1. Identify and sketch the system (see Figure P.1 on the following page).
Step 2. Identify the unknowns. The unknown is _Q:
Step 3. Identify the type of system. It is a closed system.
Step 4. Identify the process connecting the system states. The bulb does not change its thermodynamic state, so its
properties remain constant. The process path (after the bulb has warmed to its operating temperature) is U = constant.