The Principles of Thermodynamics; With Special Applications to Hot-Air, Gas and Steam Engines

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1889 Excerpt: ...air be forced at every stroke into the hot space, and then with an increased volume, due to the heating, enter the working cylinder and drive the piston there with constant pressure through a certain, distance, and then act expansively for the rest of the way. If the engine is open it is then discharged with tolerably high temperature into the air. If the engine is closed heat is abstracted, until its temperature is the same as its original temperature, at the beginning of the cycle process. Let the air in the feed cylinder be compressed until its tension is pi, and its temperature therefore rises from T to Tx. We have then, from Equations XXIa and XXK, or T=T(fyTM w If T7, and jt are known, 2 can be found.' Now the work L, which must be performed in raising 1 kilogram of air by compression from the temperature T to Tu is by Equation XXII6, therefore the work necessary to raise G kilograms from T to is As soon as the air in the feed pump has reached the tension pu the valves open, and the compressed air is gradually forced into the heating apparatus. Here it receives the temperature T2, at which, under tolerably constant pressure p, it moves this working piston until the entire amount of compressed air has been heated, and has passed into the working cylinder. Then, as already described, the air acts expansively during the rest of the way, until its pressure pl has sunk to p. The work L, performed by the feed pump in forcing the compressed air into the heating apparatus, is, if Hx is that portion of its stroke during which the air is forced out: lLi=fE1p1. The weight of air is then also given by r_fSlp1 BT,' hence we have 16 L = RTXG (4). Now, while the feed piston is compressing the air and forcing it out, the atmosphere helps it, and its work is, I =/Hp. ...