Greetings,
I'm studying for the exam in April and I've come across a problem in the Chemical Engineering PE Sample Exam 2nd Edition by Das, Additional Problems, #3.33.
The problem is as follows:
Air is flowing in a 20" ID duct at 220 deg F and 750 mm pressure. A pitot tube positioned at the center of the pipe's cross section shows a manometer reading of 4" water column. The pitot tube coefficient is 0.98. Viscosity of air = 0.22 cP. The air flow rate, expressed in scfm at 60 deg F and 1 atm through the duct is most nearly:...
In the answer section I've understood everything up to the point where they calculate an average velocity. They pulled 0.82 from somewhere and I have no clue where they got it from. I've referenced the Pitot tube section in the Chemical Engineering PE License Review 3rd Edition by Das (full of mistakes by the way) pg. 146, Ex. 4.4 and it says "At this value of Reynolds number, Vavg/Vmax = 0.82" and has a reference of Chemical Engineer's Handbook, 5th ed., Perry p.5-11.
I have Perry's 8th edition. I believe they are referring to p.6-11 in my edition which is part of the topic Incompressible flow in Pipes and Chanels. I don't see any chart relating the Reynolds number to a velocity coefficient. I've researched this for about 20 min online and in several other texts and I can't find what relationship the problem is referring too. It's gotten to the point where I'm passed trying to solve the problem and just want to know what they are talking about.
If someone...anyone... could either let me know what the topic is in Perry's 5th edition that the review manuals are referring too, or give me the name of the relationship they are using I'd GREATLY appreciate it.
Thanks
I'm studying for the exam in April and I've come across a problem in the Chemical Engineering PE Sample Exam 2nd Edition by Das, Additional Problems, #3.33.
The problem is as follows:
Air is flowing in a 20" ID duct at 220 deg F and 750 mm pressure. A pitot tube positioned at the center of the pipe's cross section shows a manometer reading of 4" water column. The pitot tube coefficient is 0.98. Viscosity of air = 0.22 cP. The air flow rate, expressed in scfm at 60 deg F and 1 atm through the duct is most nearly:...
In the answer section I've understood everything up to the point where they calculate an average velocity. They pulled 0.82 from somewhere and I have no clue where they got it from. I've referenced the Pitot tube section in the Chemical Engineering PE License Review 3rd Edition by Das (full of mistakes by the way) pg. 146, Ex. 4.4 and it says "At this value of Reynolds number, Vavg/Vmax = 0.82" and has a reference of Chemical Engineer's Handbook, 5th ed., Perry p.5-11.
I have Perry's 8th edition. I believe they are referring to p.6-11 in my edition which is part of the topic Incompressible flow in Pipes and Chanels. I don't see any chart relating the Reynolds number to a velocity coefficient. I've researched this for about 20 min online and in several other texts and I can't find what relationship the problem is referring too. It's gotten to the point where I'm passed trying to solve the problem and just want to know what they are talking about.
If someone...anyone... could either let me know what the topic is in Perry's 5th edition that the review manuals are referring too, or give me the name of the relationship they are using I'd GREATLY appreciate it.
Thanks