University:
Swansea University
Course:
EG-086 | Engineering Science
Academic year:

2023
Views:

131

Pages:

4
Author:

Lloyd R.

veselay Ollory to God jem by a cartoon Aymar Additional derivation. The net work done per kg in the Otto cycle Can also be expressed in terms of Pre. It. P is expressed in bat ive; 105 N/m², then work done. W= 5-1 5-1 X10 KJ. Also, P P Ap, nihere up stanch for pressure ratio. (()) ((1-8) (173))・M Mean effective pressme (Pm) is given by::. Pm= - Pets-PMI(-2) -1 5-1 ber also in-in Pos[(-1)(x-1))] 24-42 PP[(x-1)(x-1)] -1 Im Work done Stroke volume PPR-L1) (AP)] (1) (1) Constant Polessure or Diesel Cyade cle was introduced by Thi's Cycle D. P. Diesel in 1897. It cliffers from Otto cycle in that heat is supplied at constant pressure instead of at constant volume. This Cylle comprises of the following operations: (1) 1-2- Actiabatic Compression (n) 2-3- Addition of heat at constant pressure. (in) 3-4-Adiabatic expansion) (n) Rejection of heat at constant volume. Acliabatic Pa Const. V Const Adiabatic Point 1 represents that the cylinder is full of ais. Let P., Vi Cowesponding pressure, Volume and absolute temp. The piston then compresses the air adiabatically (ix; Puc) till the values belome P, V₂ and To respectively at point 2. Heat is then added from a hot borly at a constant pressure. Dwing this addition of heat let volume increases from V2 to Vs and temperature is to Ts, Cowesponding to point 3. and I be the Cowes, Point 3 is called the point of cut-off. The ait then expands adiabatically to the Conditions Pa, Va and To respectively Correspondry b point 4. Finally, the als rejects the heat to the Cold body at Constant volume till the point 1 where it returns to its orginal state Consider 1 kg of air. Heat Supplied at constant pressure - ep (T₃-72) -(T-Ti) Heat rejected at Constrand Volume Ca he Can of the Otto See the efficiency of diesel cycle cycle only in than always greator- is different from that the (bracketed factor) unity 1. This factor is because P>1. Hence for Comprestion ratio, the otto cycle is move efficient. e given empreced in terms of The net work for diesel cycle can be expressed in terms of Pu as follows: W= B(14-15) + By-P424 -1 The last expression will be [√(1-1)-(R) (-1)] (-1) W Mean effective pressure Po is given by!! Work done Stroke volume