大学物理(热学) 1) Review 2) Carnot's cycle eNtropy 2006-12-21 2021/9/5
2021/9/5 1 大学物理（热学） 1) Review 2) Carnot’s cycle 3) Entropy 2006-12-21
High temperature High-pressure ste from boiler Steam Water Intake valve Boiler ng expansion) Exhaust valve Piston (closed during expansion) Pump pressure steam, exhausted to condenser Wat temperature FIGURE 20-2 Steam engines (a)Reciprocating type (b)Turbine(boiler and condenser not shown)
FIGURE 20-3 Four-cycle internal combustion engine: (a)the gasoline-air mixture flows into the cylinder as the piston moves down:; (6) the piston moves upward and compresses the gas; c) firing of the spark plt plug ignites the gasoline-a mixture, raising it to a high temperature; (d) the gases, now at high temperature and pressure, expand against the piston in he power stroke; (e) the burned gases are pushed out to the exhaust pipe; the intake valve then opens, and the whole cycle repeats. Intake Exhaust Both valves Both valy alve Both valves Exha closed To exhaust Ga . cylinder ixture from carburetor Rings Connectin rod Crankshaft Intake (b)Compression (c)Ignition(d)Expansion (e)Exhaust (power stroke)
用热做功—存在限制否?
用热做功——存在限制否？
Carnot's ideas
Carnot’s ideas Q W