1. Dr. AbdelSalam Al-Sarkhi
Thermodynamics 1 ME 203
Dr. AbdelSalam Al-Sarkhi

2. Outline Textbook Catalog Description Grading system Homework
Attendance
Exams
What thermodynamics
Topics to be covered during the course
Application Areas of Thermal-Fluid Sciences

3. Text Book 6th Edition THERMODYNAMICS An Engineering Approach By
Yunus A. Cengel and Michael A. Boles

4. Catalog Description: Thermodynamics 1
System and control volume concepts.
Properties of a pure substance.
Work and heat.
The first law of thermodynamics as applied to a system and a control volume,
internal energy, enthalpy.
The second law of thermodynamics.
Carnot cycle,
entropy,
reversible and irreversible processes.
Applications of steady state steady-flow, uniform-flow, and other processes.

5. Grading System 10% Class Test 10% Homework Assignments 20% First Exam
15% Second Exam
15% Quizzes
30% Final Exam

6. Homework Homework problems are 5 problems every week.
All homework problems assigned during a given week are due in class one week later unless stated otherwise.
Late Homework will not be accepted

7. Attendance Attendance will be checked during each lecture.
Excuse should be authorized by the Deanship of Student Affairs and submitted one week later after resumption of class attendance.
Any student having more then 9 unexcused absences will receive a grade of DN for the course.

8. Location: Building 22 Room # 157-1 Phone 860-7725
Office Hours
Office Hours:
1:00 – 2:00 SMW
11:00-12:00 ST
Location: Building 22 Room # 157-1
Phone

9. Air-conditioning systems Refrigeration systems
Application Areas of Thermal-Fluid Sciences
Power plants
The human body
Air-conditioning systems
Airplanes
Car radiators
Refrigeration systems

10. Dimensions and Units
Basic Dimensions, Primary or Fundamental such as mass, m, Length, L ,time, t, and Temperature, T
Secondary Dimensions or Derived such as velocity V , Energy E and Volume V
Two systems of Units
English system, which is also known as the United States CustomarySystem (USCS), and
The metric SI (from Le Système International d’ Unités), which is also known as the International System.
The SI is a simple and logical system based on a decimal relationship between the various units

11. Dimensions and Units
The seven fundamental dimensions and their units in SI (International System).

12. Decimal Relationship Between Units: SI System

13. Dimensions and Units

14. Dimensional Homogeneity
E = 25 kJ +7 kJ/kg =?
E = 25 kJ +7 km/kg =?
E = 25 kJ +7 kJ = 32 kJ
So the mistake is kJ/kg must be kJ
All sides must have the same units

15. Unity Conversion Ratios or Conversion Factor
If we have 100 lbm ft/s2 how many lbf do we have?
Anything multiplied by 1 is the same
Answer = lbf ……………do it
12 inch = 1 ft ; how many foots in the 23 inch
Answer = ft …………do it

16. Temperature and the Zeroth Law of Thermodynamics
Not in Thermal
Equilibrium
in Thermal
Equilibrium
The zeroth law of thermodynamics states that: If two bodies are in thermal equilibrium with the third body, they are also in thermal equilibrium with each other or
The equality of temperature is the only requirement for thermal equilibrium.
two bodies are in thermal equilibrium if both have the same temperature reading even if they are not in contact

17. Temperature scales
Note: it makes no difference to use K or C in formulas involving temperature difference. However, you should use Absolute temperature in formulas involving temperature only like the ideal gas low.

18. Basic Concepts of Thermodynamics

19. What is Thermodynamics
Thermodynamics (from the Greek words therme (heat) and dynamis (power)), is the science that primarily deals with energy.
Thermodynamics is the study of the effects of Work, Heat and energy on a system. So thermodynamics is the science of Energy

20. What is Thermodynamics
Zeroth Law: Thermodynamic Equilibrium and Temperature
First Law: Work, Heat, and Energy
Second Law: Entropy

21. Thermodynamics
The first law of thermodynamics is simply an expression of the conservation of energy principle, and it asserts that energy is a thermodynamic property.
Energy cannot be created or destroyed; it can only change forms (the first law).

22. Thermodynamics (continued)
The second law of thermodynamics asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy.
For example, a cup of hot coffee left on a table eventually cools to room temperature, but a cup of cool coffee in the same room never gets hot by itself.
Heat flows in the direction of decreasing temperature.

23. Heat Transfer
Thermodynamics deals with equilibrium states and changes from one equilibrium state to another.
Heat transfer, deals with systems lacking thermal equilibrium, and thus it is a non-equilibrium phenomenon.
Temperature difference is the driving force for heat transfer. The larger the temperature difference, the higher is the rate of heat transfer.

24. Closed Systems
A closed system (or simply a system), or a control mass, is defined as a quantity of matter or a region in space chosen for study. The mass or region outside the system is called the surroundings.
The real or imaginary surface that separates the system from its surroundings is called the boundary.

25. Closed Systems
No mass can cross its boundary But energy can.

26. Closed Systems with moving boundary
Consider the piston-cylinder device shown in the Figure. Let us say that we would like to find out what happens to the enclosed gas when it is heated. Gas is our system. Since no mass is crossing the boundary, therefore, it is still a closed system but with a moving boundary

27. Closed Systems vs open systems

28. Open Systems
An open system, or a control volume, is a properly selected region in space.
Both mass and energy can cross the boundaries of a control volume.
It usually encloses a device that involves mass flow such as a compressor, turbine, or nozzle. Flow through these devices is best studied by selecting the region within the device as the control volume.

29. Open Systems (continued)

30. Approaches Macroscopic Approach (Classical Thermodynamics)
- is concerned with the overall behavior of a system
- no model of the structure of matter at the molecular, atomic,
and subatomic level is directly use
Microscopic Approach (Statistical Thermodynamics)
- is concerned directly with the structure of matter
- characterize, by statistical means, the average behavior of
the particles making up a system of interest and relate this
information to the observed macroscopic behavior of the
system

31. Properties of a System
Any characteristic of a system is called a property. Some familiar properties are pressure P, temperature T, volume V, and mass m.
Properties describe the state of a system only when the system is in an equilibrium state.
Not all properties are independent. Density is a dependent property on pressure and temperature.

32.  = 1/  Density as a property Density is mass per unit volume;
 = mass/volume (kg/m3)
Specific volume is volume per unit mass.
 = Volume/mass, (m3/kg)
 = 1/ 