作者coffee1205 (佐岸)
站内TransPhys
标题[热能]热力学otto cycle 问题
时间Thu Mar 19 22:43:06 2009
这题想很久想不出来 Otto cycle:
题目:The compression ration an Otto cycle is Va/Vb = 8.00.At the beginning of
the compression process ,500 cm*3 of gas is at 100kPa and 20度(摄氏).At the
beginning of the adiabatic expansion ,the temperature is 750度(摄氏).Model the
ideal gas with E(int){int是下标}=nCvT=2.5nRT and γ=1.4
Find the number of crankshaft revolution per minute require for a one-cylinder
engine to have an output power of 1000w=1.34hp .
NOTE:The thermodynamic cycle involves four piston strokes.
我看解答是降写的Let f represent the angular speed of the crankshaft. Then
f/2is the frequency at which we obtain work in the amount of 84.3 J
1000=(f/2) x 84.3
-->f=1.42 x 10*3 rev/min
我不懂的地方是,为什麽要除以二?有人可以告诉我吗?感激不尽喔!!
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 123.204.212.64
※ 编辑: coffee1205 来自: 123.204.210.150 (03/20 21:56)