mellotango

I am quite new to turbochargers and am researching a project that involves the use of turbochargers. I have a question about the force generated on the compressor outlet. We understand the exhaust gas directed into the turbine side of the turbocharger, which in turn spins the shaft wheel, and the residual exhaust gas exits the outlet of the turbine. So when the shaft spins, it also drives the compressor wheel which sucks in and compresses the air, and pushes it out of the compressor outlet.

My question is, when this compressed air exits the compressor outlet, is the force or thrust of this airflow, same as the force/thrust of the exhaust gas exiting the turbine outlet, since the shaft is working both the turbine and compressor wheel simultaneously? And can the force/thrust at the compressor side be adjusted to be less, same or more than the force/thrust generated at the turbine outlet?

Matt Cramer

It isn't the same as the turbine inlet force. Take the boost pressure and multiply it by the compressor outlet area. F=PA.

marvg

I am new to this too. As I said in my intro at marvg I am not wanting to go fast but produce power to pull my travel trailer. I see mention of 100K RPM as kind of a minimum but is that a minimum for a go fast car or just a minimum to produce enough air flow to produce power. Can there be pressures at a lower turbo speed that might make enough power for my needs. Does the size of the compressor come into play? I see this question that brought my question to mind is from 2013 and I may not be posting this correctly but is you see it and have some answers please send it to marvg. marvg

Matt Cramer

It sounds like what you're really asking is how to match a compressor to your engine. There are several in depth articles on this - it's a long subject. Here is one that you can get online:

How to Match a Turbocharger to Your Engine: Step-by-Step Guide

marvg

Hello Matt,


Thanks for the reply and I have ordered the book. Lots to learn. The article talked only about using exhaust gases to run the turbine. I have read about electric motors and belts (would that make it a supercharger?. How well do these work and I am not talking about the $60 kits made of plastic and producing imaginary boost. The electric appeals to me as I can turn it off when not needed or adjust the motor's speed to increase or decrease the boost as needed but they talk about a bunch of batteries and used for short bursts. I would want something that would work for long durations. Do you have any insight into this. Thanks, Marv Gonser

Matt Cramer

Belt driven would be a supercharger.

Electric driven would require an integral horsepower motor, probably around 5 hp or so depending on what boost you're looking for, to turn a supercharger. This usually means a fairly large AC motor and a 200+ volt inverter circuit to drive one.

marvg

Thanks Matt, I do see on youtube that there are various individuals working on electric motor driven turbochargers. Not sure of their success as yet. There are various car companies with them coming down the pike and some racing organizations (F-1?) are beginning to use them to spool up the turbo before the exhaust drive kicks in such as coming out of a turn. I have seen some belt drives also on youtube but a lot of trouble with keeping the belt on. Thought this along. Marv