Pipe Bends and Head Loss

45deg bend is most appropriate. Big radius the better, less head loss.

I beg to differ.

There is no doubt; bigger the radius, the better it is. If space is restricted, different angles can be tried to have as smooth a flow as possible.

raj thakral

The smaller the angle of deflection the smaller the head loss. Head loss factors can be found in most hydraulic engineering books. The head loss is also a result of the type of pipe, the lining of the pipe, and the fitting and its lining if different than the pipe itself.

Anything that creates turbulence is bad.

Reynolds Number Calculator

• Good site my dear lynlynch, and it is important to calculate the Re to be used in calculating the total friction loss in the system. So, we can use the following link from the same site: Pipe Pressure Loss Calculator.

• See the following CR4 Thread for the same subject: Pressure drop in piping for specification of Pump disch. pressure.

• For friction losses in fittings like elbows, reducers, valves, ... etc., there are a lot of handbooks explaining that article, where some of them consider the fitting or valve as an equivalent length of the pipe (e.g the 90^o elbow is equivalent to a length of 20 D, where D is the pipe diameter), and others provide a monograph to find directly that friction loss.

Thanks for the compliment.

As we say in Arkansas, even a blind hog finds an occasional acorn.

As few as possible.

This Question is very general.

Best Engineering judgement is to have as few bends as are possible.

However there are many other factors which influence the Head loss in a pipe such as

1. size of pipe

2 Material of pipe

Routing of pipes and space constraints. If there is no restraint and pipe material is copper/ steel, for a small dia pipe, answer is different.

Normally as straight a pipe routing can be, the friction loss will be less and thus the head loss

Even controlling the velocity can also reduce loss in pipe.

Any Specific question can be answered in specific way.

MR Raj Thakral

Actually with the information provided to date, insufficient information to establish that one or more bends would cause any head loss whatsoever is available.

Only when there is a significant flow rate in a small pipe does head loss occur whether or not bends are present.

"Only when there is a significant flow rate in a small pipe does head loss occur whether or not bends are present."

I hope you are not the same person who invaded another thread with negatives.

How can you have movement without friction? And if you have friction, you have head loss. At what velocity is it possible to transport fluids without any losses. You can make a fortune if you can pump water without an energy input.

Well, for example:

An 8 inch sch 40 new steel pipe carrying 50 gpm would have a friction loss of 0.21 feet per 1000 feet, very small indeed.

While that same pipe carrying 6000 gpm would have a friction loss of 678 feet per thousand feet, very large indeed.

In the former case, adding bends would be insignificant while in a latter case, these same bends would have a significant effect.

This information is coming straight out of Cameron Hydraulic Data Handbook, 19th edition page 3-63 (based upon Darcy Formula).

<...Only when there is a significant flow rate in a small pipe does head loss occur whether or not bends are present....>

That's codswallop; <...head loss...> occurs in all pipes whether <...small...> or not. Here is how to calculate it:

Darcy–Weisbach equation - Wikipedia

The <...head loss...> at <...pipe bends...> and at other fittings is usually dealt with empirically by an additional length equivalent to so-many-diameters of straight pipe being added in to the actual length.

Hmm...In calculating flow a general rule could be to add 3' to the length of pipe to account for each elbow fitting.

As few bends as possible and use sweeps instead of elbows.

The biggest radius you can fit in the given space.