Reciprocating compressor performance can be measured in many ways and is now becoming more of a common activity for engineers to monitor their compression equipment. So what are we looking for when we want to measure compressor performance in a simulation?
A quick search on the web and most of the major manufacturer’s can give anyone out there the tool they need to simulate a compressor. It’s not for the beginner, these programs need a lot of input in the setup stages that has to be collected at field level, that is on the machine. So doing a simulation remotely is going to require at least one visit to the machine to see how it was actually configured and what the unit actually looks like. If you haven’t been to a site to see these machines in action, there can be some differences in design after it leaves the manufacturer that aren’t going to be on the build sheet. Too often I see many simulations go way off course due to a simple geometry change on the machine.
FIELD TIME!!! Get out your pens and paper and start jotting down all the information you can on the unit. Get serial numbers, cylinder bores, clearances, volume pocket positions, unloaded cylinder ends, stages, number of suction and discharge valves, and overall position on the frame to make an accurate write-up of the units configuration. You can never have too much information on field trips. There is nothing worse than coming back to the office and having wished you spent another 2 minutes copying down information. Look around the unit and jot down operation conditions like temperatures of the suction systems, discharge of each cylinder, and panel pressures. If you can, compare any machine installed gauges to the ones on the panel. Use your eyes and ears and feel your way around the unit to get a level of comfort with its operation. Get a metered flow if available, that can help later on in the analysis portion.
ASK LOTS OF QUESTIONS! The operator of the unit is the best friend you could have to get the real world experience of what goes on in a day. They can tell you stories about pressure and speed changes, temperatures that vary with the seasons. All kinds of things that can help you determine if your simulations are going to be accurate.
ACCURATE GAS ANALYSIS. Can’t leave without that. You need to have an accurate account of what that thing is pushing through in a day. Think about how the compressor is used and where a good existing sample would apply or go and have one done.
TIME TO INPUT. When you are a happy with all of that, then its time to head back to the desk and start to input what you have collected. It’s true that the setup of the simulation run is probably 90% of the work. After that you can start to fine tune your model to more closely fit the real world conditions.
Stay tuned for the next part of the series where we get into the simulation and then the meat and potatoes of online recip analysis.
