Engineering Flashcards
Second law of thermodynamics
In order for work to be done heat must flow
Why is work done on refrigerators
You need to get heat from cold place to hot place so you need to put in work
What is mechanical power
Power used in overcoming friction
What is overall efficiency
How energy in fuel is converted to useful power
What is thermal energy
How well calorific value is converted to work
Cop
The heat energy delivered divided by the work put in
Advantages and disadvantages of of diesel engine
More expensive to produce
More robust
Advantages
Does not require spark
Can provide more torque
Better fuel efficiency
What is indicated power
This is the theoretical power capability
What is crankshaft
The engines flywheel
What is output or brake power
The measure of engines power without the loss in power
What is one horsepower ( 1bhp
746 W
What is input power
Input power is the energy released as the fuel burns
What is the brake power
It is the power needed to maintain constant angular momentum
Overall efficiency
Is mechanical efficiency x thermal efficiency
Limitation of real heat engines
Petrol air mixture behaves as ideal gas
Which is not the case in real life
The processes that form the engine cycle are reversible
