Potto Home | Contact Us | |
Next: Examples of Fanno Flow Up: Fanno Flow Previous: The Trends Index The working equationsIntegration of equation (9.25) yields A representative friction factor is defined as By utilizing the mean average theorem equation (9.36) yields It is common to replace the with which is adopted in this book. Equations (9.24), (9.27), (9.28), (9.29), (9.29), and (9.30) can be solved. For example, the pressure as written in equation (9.23) is represented by , and Mach number. Now equation (9.24) can eliminate term and describe the pressure on the Mach number. Dividing equation (9.24) in equation (9.26) yields The symbol ``*'' denotes the state when the flow is choked and Mach number is equal to 1. Thus, when Equation (9.39) can be integrated to yield: In the same fashion the variables ratio can be obtained
The stagnation pressure decreases and can be expressed by Using the pressure ratio in equation (9.40) and substituting it into equation (9.44) yields And further rearranging equation (9.45) provides The integration of equation (9.34) yields The results of these equations are plotted in Figure (9.2) The Fanno flow is in many cases shockless and therefore a relationship between two points should be derived. In most times, the ``star'' values are imaginary values that represent the value at choking. The real ratio can be obtained by two star ratios as an example A special interest is the equation for the dimensionless friction as following Hence,
Next: Examples of Fanno Flow Up: Fanno Flow Previous: The Trends Index Created by:Genick Bar-Meir, Ph.D. On: 2007-11-21 |