PhyII_LPO_Chapters 18, 20,21,22. capitulos del serwaypt
thermodynamic chemistry-heat engine
1. ASSIGNMENT CHM 458
CHEMICAL THERMODYNAMICS
AS225 PART II 2012/2013
TITTLE : HEAT ENGINE
NAME : NURUL SABIRAH BINTI MOHD SALEH
I/D : 2011581687
LECTURER : DR MD NOOR BIN ZAKARIA
DATE SUBMIT : 27 DECEMBER 2012
2. INTRODUCTION TO ZEROTH LAW,FIRST ,SECOND ,AND
THIRD LAW OF THERMODYNAMICS
ZEROTH LAW
The zeroth law states that if two systems are in thermal equilibrium with a third system, they are
also in thermal equilibrium with each other.It can also be defined as that if two systems, A and B,
are in thermal equilibrium with a third system, C, then A and B are in thermal equilibrium with each other.
FIRST LAW OF THERMODYNAMICS
First law of thermodynamics state that energy cannot be destroyed or created.It shows the
principles of conservation of energy.
SECOND LAW OF THERMODYNAMICS
Second law of thermodynamics state that the entropy of an isolated system never decreases,
because isolated systems spontaneously evolve towards thermodynamic equilibrium.
THIRD LAW OF THERMODYNAMICS
The third law of thermodynamics is stated as the entropy of a perfect crystal at absolute zero
Kelvin is exactly equal to zero.
Now what I am going to do in this assignment is based on these 4 laws of thermodynamics.I’m
using my own car engine to be a model for the heat engine.I have study all 4 laws and I am going
to relate them to my car’s engine.
The type of engine that I am using is 1.3 litre K3-VE engine with four in-line cylinders; both
engines employ Dynamic Variable Valve Timing (DVVT) systems and conventional electronic
fuel injection (EFI).
3. Hot air region or This is an overview of outer part of
engine
hot reservoir at Th
Engine
This is what happened in the
cold reservoir, Th
Heat engine is a system that
performs the conversion of heat
or thermal energy to mechanical
work.
It does this by bringing a
working substance from a high
temperature state to a lower
temperature state. A heat
"source" generates thermal
energy that brings the working
substance to the high temperature
state.
Carnot Cycle occur here
(1st law of thermodynamics)
4. HOW I RELATE THOSE LAWS IN THE CAR ENGINE
FOR FIRST LAW-CARNOT CYCLE
Carnot heat engine consists of 5 main parts that is cylinder,source,sink,working substance and an
insulating pad.Cylinder,which is the main part of the carnet engine has insulating walls and conducting
base.It is suited with a perfectly insulated and frictionless piston.Source,the source is a very hot body
maintain at a peaks higher temperature and has infinite thermal capacity.By infinite thermal capacity we
mean that any amount of heat can be taken out of it withut changing the temperature of the
source.Sink,is a body at low temperature, T2 also has infinite thermal capacity that is any amount of
heat can be added to it without changing its temperature.Working substance,it is the ideal gas which
absorb heat from the source,does some mechanical work and recheck the remaining amount of heat
into the sink.Insulating pad or insulating stand,during the operation the Carnot cycle,working substances
undergo adiabatic expansion and adiabatic compression.The cylinder is placed on insulating pad which
is thermally isolated working substance from the surrounding.To continue supply work,the working
substance is taken to the series of operating system called the Carnot cycle.The Carnot cycle consist of
two reversible isothermal and adiabatic processes.Carnot Cycle is obtain when ideal gas is used as the
working substance.The ideal gas is taken inside the cylinder to the piston.
FOR SECOND LAW
Second law gives the direction of the heat flow that are from hot region which is high energy to cold
region which is low energy.Heat energy is never completely converted to mechanical energy that is
efficiency of the heat engine is never equal to 100%.Efficiency of an engine can be defined as the ratio of
external work done to the amount of heat absorbed from the source.There are two types of engine
which is external combustion engine and internal combustion engine.For this car engine is internal
petrol engine.Heat flow from hot reservoir to cold reservoir.This is how second law is applied.
FOR THIRD LAW
In heat engine,third law is applied when