MECHANICAL ENGINEERING: Thermodynamics - Closed system, piston-cylinder, Boyle's law, Constant Temperature, Parabolic curve

CLOSED SYSTEM: piston-cylinder

conditions:

Temperature is constant, T = c


Boyle's law:  Absolute pressure is inversely proportional to the volume of a gas

pV = constant

pV = k

p1V1 = p2V2


curve: Parabolic


where:

p = pressure of the gas. p1, p2 are the pressures of the gas at points 1, 2

V = Volume of the gas. V1, V2 are the volumes of the gas at points 1, 2

k = constant


1. A certain gas in a piston is compressed to a volume of 12 L. Its original volume was 21 L at 10 bar. Find the new pressure if the temperature remains constant.

find:

p2 = pressure corresponding to the compressed volume


given:

V2 = 12 L

V1 = 21 L

p1 = 10 bar


solution:

p1V1 = p2V2

10 * 21 = p2 * 12

p2 = 210/12

p2 = 17.5 bar