Identical compressors working in parallel

[rafcu]

Hello colleagues,

I have a centrifugal compressors map performance: relating Polytrophic Head vs. Inlet Flow and representing the speed curves and efficiency curves.

My question is:

How from this curve can I obtain the curve representing this both identical compressors working in parallel?

My concern is the overall efficiency, how can I obtain the efficiency for two identical compressors working in parallel if I have the efficiency of one individual compressor?

Thanks and regards,

 

[zdas04]

What's the matter, didn't you like the answers you got to this question in thread798-148532 ?

David

 

[rafcu]

In the referenced thread there is just one partial answer that not satisfies me completely for this reason I changed the forum reformulating the question, any problem?

 

[zdas04]

Dual posting is not well thought of here, it doesn't allow future posts to build on earlier posts.

You might have learned from the responses that you got in the first thread that people here are very willing to jump through all sorts of hoops if they have enough information to get their teeth into.

I wouldn't have brought this up if you had started with the information that people were begging you for in the first thread in your post, but instead you cut and pasted the same question you started the last thread with with at least the addition of the type of compressor.

You've ignored the perfectly valid question about your definition of effeciency. You would have been better off posting your response to Montmayor's post here than repeating your original question.

David

 

[rafcu]

Sorry, as nobody answers me the post I wrote follow to Montemayor’s remark, I though that nobody understood it. I decided change to the compressors forum. I well noted your remark, and in the future in order to respect the forum order I won’t do dual posting anymore

I apologize

 

[djack77494]

rafcu,
I also find it hard to understand what exactly it is you are trying to determine (as well as why). Nonetheless, I will attempt an answer.

I think you're talking about a fairly simple system - two identical single stage compressors. Both have the same inlet conditions and each should operate at the same speed and take 1/2 of the total flowrate. If that's true, just take hapf the total flowrate and look up the efficiency (and speed) on your map. Both compressors will operate at the same efficiency, so that is your average efficiency as well. Am I missing anything?
Doug

 

[rafcu]

Thank you Doug,

You have well understood the problem, and I well understood your answer, it is enough for me…