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[Art Montemayor]

Pankaj:

Please do not post multiple copies of your query in other Forums. This is very distracting and confuses everyone about just which thread to respond to. It is very unproductive and creates chaos.

You say you are working on a centrifugal compressor design, although you don't have any prior experience of doing this. Additionally, you state that nobody around you has any idea about the subject. Allow me to ask why you, an inexperienced engineer, are doing this and for what purpose? Your product will undoubtedly be under scrutiny – even by yourself. So, why go through this exercise without any local guidance, mentorship, instruction, and leadership? If this is an industrial application, it is not logical.

The use of Computational Fuid Dynamics (CFD) is impressive – from an academic point of view. But what does that do to the credibility of the produced results? At best, CFD is a theoretical number crunching and developmental tool. But it is always subject to confirmation with actual field tests. Without the expensive confirming field and lab tests, the results are not credible.

Why don’t you do what we all do: fill in a Specification Sheet and submit it to a recognized, experienced, and proven designer and fabricator of centrifugal compressors for a quote?

If you think you have problems with the inlet guide vanes, wait until you get to the diffuser section. And you haven’t yet gotten to the control problem due to the potential surges your product will be subject to. And the required seals are another formidable problem. You will have to produce reliable, credible performance curves for your compressor and you will have to back them up with substantial guarantees. I assume you have the capital monies to finance all these requirements because potential buyers will immediately require that.

I've installed and operated many centrifugal compressors and labored with maintaining them on line and free from surges. It is very difficult for me to imagine that someone who has no prior experience can "develop" a credible, working, acceptable model - with or without CFD.

But I wish you a lot of luck.

[Art Montemayor]

Pankaj:

Although you don’t identify your location, I believe you to be in a developing country and seeking to start your own centrifugal compressor industry. I think that is admirable and I commend you for the effort. That is one of the reasons for responding to your requests. Now to the points you’ve raised:

1. You now reveal you are trying to develop your own product to compete with the existing major manufacturers. This is good, as I said, but I believe you are going about it in a wrong manner in order to be successful. You are not about to succeed when you haven’t designed and much less built a unit on your own. You need to accumulate the existing expertise and experience – at the very least. The way to go about that is to work directly in the industry and “get your hands dirty” by actively designing and fabricating these compressors. For example, get a job working for Alfa-Laval for about 5 – 10 years and learn how they design and build their machines. Without experience such as this, you have little chance for success. You are not going to find the experience and expertise for free in Internet Engineering Forums. Fabricators and designers are not going to give you (for free) the information and expertise that it cost them years and investments to obtain. That’s my answer to your first point.
2. There is nothing “bad” in doing what you are attempting; I think I have been clear in describing this as a good – not a bad thing. To presume that others take what you are doing as “bad” is a rash and immature attitude. I don’t think you mean it that way, but that’s the way it is interpreted.
3. The real, substantial source of credible and proven technology for centrifugal compressors lies in the centrifugal compressor design and fabrication field. Most of the conventional compressors have already been designed. I don’t think your application is so novel or unique that it hasn’t been designed for and modeled yet. If your application is indeed unique, then it will be limited in the number of fabricated units required; and if that is the case, the unit Capital Cost will be much higher than for existing, proven, “on-the-shelf” designs.

Explaining how a proper suction inlet guide vane should be designed and built on an Engineering Forum entails not only some liability, but a lot of faith. First, and foremost, information involving existing centrifugal compressors is, as I explained, PROPRIATARY. To divulge or sell this information is contrary to engineering ethics and, in most countries, to the existing laws. That’s why, as I stated, the fastest and most efficient manner of getting indoctrinated and experienced in the industry is to actually get involved in it as an employee. You will be required to sign the usual documents which limit you in competing with your employer for some future years, but after that you are free to use the information you have accumulated – as a consultant or a competitor.

I wish you luck.