Quizlet

Thermodynamics Overview

Definition: Study of energy in the form of heat and work, and the fluids used to convert heat to work.
Energy Forms:
- Most abundant form: Heat
- Most useful form: Work
Essential Component for Conversion: Fluid is required for converting heat to useful work.
Applications of Thermodynamics: Electrical wiring is not included as an application of thermodynamics.

First Law of Thermodynamics: Related to the principle of conservation of energy.
Pioneer of Thermodynamics: William Rankine authored the first thermodynamics textbook.
Energy Quality Determinant: Controlled by Temperature.

Basic Unit of Mass in SI Units: Kilogram (kg).
Basic Temperature Unit in SI: Kelvin (K).
Basic Mass Unit in English Units: Pound mass (lbm).
Basic Temperature Unit in English Units: Degree Rankine (°R).
Pressure Conversion: 170 psi = 1,172.1 kPa.
Density Calculation: Density of liquid in a tank with mass 12,000 kg and volume 15 m³ is 800 kg/m³.
Weight Calculation: Weight (W) of a 200 lbm person at g=32.174 ft/s² is 200 lbf.

Definition: A thermodynamic system is a quantity of matter or a region in space set aside for study.
Open System: A system where mass can cross its boundaries; also known as a control volume.
- Example: A water heater that allows water to enter, be heated, and leave.
System Boundaries: Can be either fixed or movable (True).

Definition of Property: Characteristic to describe the condition or state of a system.
- Examples: Pressure, temperature, density.
Intensive Properties: Do not depend on mass or size of the system.
- Examples: Temperature, density, pressure.
- Common Representation: Lowercase letters for intensive properties except for P and T.
Extensive Properties: Depend on mass or size of the system.
- Examples: Volume, mass, area.
- Common Representation: Uppercase letters for extensive properties.

Density Equation: ρ = m/V (where m is mass and V is volume).
Specific Volume of a Gas: For density 2.85 kg/m³, specific volume is 0.351 m³/kg.

Definition of State: Condition of the system at a specific time.
Equilibrium: A system is in equilibrium if properties do not change when isolated from surroundings.
State Principle: Two independent intensive properties are needed to describe a simple compressible system.
Work Modes: For a system with two possible work modes, a total of three independent intensive properties are needed.
Thermodynamic Process: The state of the system changes from one equilibrium state to another.

Steady State: Properties at a point do not change with time.
Uniform State: Properties are the same throughout the system at a given time (False if stated otherwise).
If Uniform State is Given: It indicates properties do not change from point to point at a specific time.

Isothermal Process: Example - System at T1=500 °C and P1=200 kPa to T2=500 °C and P2=700 kPa.
Isobaric Process: Example - System at T1=790 °C and P1=2000 kPa to T2=500 °C and P2=2000 kPa.
Isochoric Process: Example - System at T1=790 °C and specific volume v1=10 m³/kg to T2=500 °C and v2=10 m³/kg.
Cyclic Process: Example - System remains at T1=900 °C and P1=800 kPa to T2=900 °C and P2=800 kPa.