1. Thermodynamics Cengel-PPT a b c Apps
Prof. M. Kostic
Mechanical Engineering
NORTHERN ILLINOIS UNIVERSITY

2. What is Thermo…? Cengel-PPT a b c Apps
ENERGY Science
Energy Conversion
What is Energy…?
Cause Changes - Work, Heat, etc.
Energy is property of matter!
Therefore, ENERGY and PROPERTY interrelations

3. Thermo Vocabulary System, Surroundings, and Boundary
Closed System - Control Mass
Open System - Control Volume
Control Surface
Adiabatic System - NO Heat Transfer
Isolated System - NO Energy Transfer

4. Forms of Energy TOTAL Energy Macroscopic vs. Microscopic
thermal, kinetic, potential, electric, magnetic, nuclear, ….
Macroscopic vs. Microscopic
INTERNAL Energy (U) - sum of ALL microscopic energies

5. System PROPERTIES
Extensive
m, V, U, E
Intensive
T, P, r, u, e

6. State, Equilibrium, Processes
State or Condition of a System
Equilibrium - System in balance, NO Changes
thermal/temperature balance - no HEAT transfer/adiabatic
mechanical/pressure balance - no WORK transfer
phase - no change of phases
chemical - no change of spices

7. Pressure Scales Gauge pressure Local atm. pressure
Absolute
Local atm. pressure
Local
atm.
pressure
Vacuum
pressure
Standard atm. pressure
kPa(abs)
psi(a)
760 mmHg(a)
29.92 inHg(a)

8. Ch.8: Temperature Measurement
Temperature: measure of hotness or coldness indicating the direction in which heat (energy) will spontaneously flow, i.e., from a hotter body (one at a higher temperature) to a colder one (one at a lower temperature).
Temperature is not the equivalent of the system energy
Historical background

9. Temperature Measurement Devices
thermocouples,
resistive temperature devices (RTDs and thermistors),
infrared radiators,
bimetallic devices,
liquid expansion devices, and
change-of-state devices.

10. 8.2: Temperature Standards
Temperature scale (ITS-90)
Definition of the degree Kelvin K, defined as the 1/ fraction of the thermodynamic temperature of the triple point of water (TPW).
Fixed (reference) points
Interpolation between the fixed points

11. Thermo Laws Zeroth Law: TA=TC and TB=TC then TA=TB
First Law - Energy Conservation
Second Law - Process Direction

12. In Conclusion Be imaginative Try to differentiate
Make sense of what you study
Work and think hard and smart
Thermodynamics is a science of
ENERGY and MATTER and their relations