for a given volume of gas,is it more efficient to compress smaller volumes of gas more no. of times or compress large volumes of gas less no. of times?
i mean, that if we have V volume of gas to be compressed from p1 to p2, is it better to compress V/2 volumes 2 times or V/4 volumes 4 times. i mean, of course, the energy needed per unit mass will be same for a process, but how will efficiency of the compressor be affected?Hi chhitiz,
I'm not sure how you mean that. Consider for example, the compression of a gas from a lower pressure, P1 to a higher pressure, P2. Let's consider a single stage of compression that has a given iesntropic efficiency. Regardless of how much gas (how much mass) is compressed, the states the gas goes through, including how much energy is needed per unit mass, is the same.
no, i guess not. i was just wondering how they decide the initial volume of gas to be compressed in an ic engine. is it for max. efficiency, or that much fuel burned pushes the piston for the required stroke?
The basic consideration is the desired power characteristic. Given an approximate air fuel ratio, it's pretty easy to calculate the mass of air required for a certain amount of torque.