Calculating Head Loss in a Mitre Bend Air Passage: A Guide for Beginners

[Trigger32]

I am trying to find the total head loss of an air passageway system but I have not taken a fluids class. I have been trying to teach myself the equations and principles but it tends to be very confusing without guidance. So here is my question:

I have a wheel-end knuckle with an air passage put through it. The passage is not a pipe but a diameter cut into the actual material (ductile iron). The passage takes two 90 degree sharp bends and then exits the knuckle. Now i am fairly certain that I understand how to calculate a straight line head drop with no bends. My confusion is coming from finding specific k-values for these pipe bends and also completely turbulent friction factors.

If someone could show me a calculation and also explain what they are doing for one bend, I think that I could solve the rest of the problem.

Here are some details of my passage:
Diameter before bend - 10 mm
Diameter after bend - 9.5 mm
Degree of bend - 90
Material Type - Ductile Iron
Initial air flow rate- 0.3 cfs

P.S. I believe this would be considered a Mitre Bend because it as a sharp angle (not sure though)

 

[firavia]

Dear Trigger32 the best way to learn is to teach yourself through Easy-learning documents and it is for your best if you print the documents and not read them online, I will give you this link that will help you in fluid mechanics and solving your problem.
http://www.firavia.com/mecheng.html

 

[Trigger32]

I appreciate your sharing this knowledge site with me, but I do not think this is helping me. I've already read through many of these short guides and for some reason I can't find what I am looking for. My problem stems from the fact that none of the charts that I can find have the specific materials and geometries of my passageways. I would like to make as little assumption as possible because this is for a real application.

My specific problem I think (unless I'm going about this the wrong way) is I can not find values for my mitered bend size. Here are the dimensions again and some added data, if anyone can just walk me through an example or post a chart, I would really appreciate it.

Dia. before bend = 10 mm
Dia. after bend = 9.5 mm
Geometry - Circular cross section
Matl. = Ductile Iron
Initial air velocity entering bend = 361.63 ft/s

Head loss per this fitting = ?

 

[shushu97]

can you please give a drawing?