Microsoft Word - Cengel and Boles TOC _2-03-05_.doc

The entropy change for a process is obtained by integrating this relation between the end states: (7–31) A second relation for t ...

and (7–36) Variable Specific Heats (Exact Analysis) When the temperature change during a process is large and the specific heats ...

Chapter 7 | 357 EXAMPLE 7–9 Entropy Change of an Ideal Gas Air is compressed from an initial state of 100 kPa and 17°C to a fina ...

Isentropic Processes of Ideal Gases Several relations for the isentropic processes of ideal gases can be obtained by setting the ...

Variable Specific Heats (Exact Analysis) When the constant-specific-heat assumption is not appropriate, the isen- tropic relatio ...

The quantity T/Pris a function of temperature only and is defined as rela- tive specific volumevr. Thus, (7–50) Equations 7–49 a ...

Chapter 7 | 361 Alternative Solution The final temperature could also be determined from Eq. 7–42 by assuming constant specific ...

7–10 ■ REVERSIBLE STEADY-FLOW WORK The work done during a process depends on the path followed as well as on the properties at t ...

give a negative result when work is done on the system. To avoid the nega- tive sign, Eq. 7–51 can be written for work input to ...

In gas power plants, the working fluid (typically air) is compressed in the gas phase, and a considerable portion of the work ou ...

Proof that Steady-Flow Devices Deliver the Most and Consume the Least Work when the Process Is Reversible We have shown in Chap. ...

Substituting this relation into the preceding equation and dividing each term by T, we obtain since Also,Tis the absolute temper ...

Isentropic (Pvkconstant): (7–57a) Polytropic (Pvnconstant): (7–57b) Isothermal (Pvconstant): (7–57c) The three processes are ...

The size of the colored area (the saved work input) varies with the value of the intermediate pressure Px, and it is of practica ...

Chapter 7 | 369 Assumptions 1 Steady operating conditions exist. 2 At specified conditions, air can be treated as an ideal gas. ...

7–12 ■ ISENTROPIC EFFICIENCIES OF STEADY-FLOW DEVICES We mentioned repeatedly that irreversibilities inherently accompany all ac ...

Isentropic efficiencies are defined differently for different devices since each device is set up to perform different tasks. Ne ...

372 | Thermodynamics Analysis A sketch of the system and the T- sdiagram of the process are given in Fig. 7–50. (a) The enthalpi ...

Isentropic Efficiencies of Compressors and Pumps The isentropic efficiency of a compressoris defined as the ratio of the work in ...

374 | Thermodynamics EXAMPLE 7–15 Effect of Efficiency on Compressor Power Input Air is compressed by an adiabatic compressor fr ...