Transcript Slide 1
THERMODYNAMICS COURSE GUIDELINES Course Learning Objectives: The objectives of this course are: Locate the thermal and volumetric properties of pure substances from the properties tables (C2). Describe the application of thermodynamics law (C2, P1) Analyse the closed system and open system in the First Law of Thermodynamics (C4, CTPS1). COURSE GUIDELINES Classes 1 hrs lecture, 2 hrs tutorial Regular and punctual class attendance is required for all students. Student Involvement: This course requires a lot of extra effort. ~ do extra exercises ~ participate actively in class and tutorials ~ search new information COURSE GUIDELINES 1 2 3 4 5 6 Assessments Test 1 Test 2 Test 3 Final Quizzes Assignments I. Individual II. Group Quantity 1 1 1 1 5 Marks Allocated 10% 10% 10% 40% 15% Expected date Week 6 Week 9 Week 12 Final Exam Schedule Throughout the course 1 1 5% 10% Week 6 Due Week 10 PROBLEM SOLVING Problem Statement Schematic Assumptions & Approximations Calculations Properties Physical Laws Reasoning, Verifications, Discussions BASIC CONCEPTS THERMODYNAMICS BASIC CONCEPTS BASIC CONCEPTS The Coal Fired Power Plant BASIC CONCEPTS BASIC CONCEPTS BASIC CONCEPTS BASIC CONCEPTS BASIC CONCEPTS THERMODYNAMICS Therme (heat) Dynamis (power) BASIC CONCEPTS THERMODYNAMICS The science that deals with heat and work and those properties of substances that bear a relation to heat and work. BASIC CONCEPTS System A quantity of matter or a region in space chosen for study SYSTEM BASIC CONCEPTS CLOSED SYSTEM BASIC CONCEPTS BASIC CONCEPTS OPEN SYSTEM BASIC CONCEPTS ISOLATED SYSTEM BASIC CONCEPTS BASIC CONCEPTS STATE OF A SUBSTANCE BASIC CONCEPTS - EQUILIBRIUM State of balance Thermal equilibrium Mechanical equilibrium EQUILIBRIUM Phase equilibrium Chemical equilibrium BASIC CONCEPTS PROCESSES AND CYCLE PROCESS – any change that a system undergoes from one equilibrium state to another Melting BASIC CONCEPTS PROCESSES AND CYCLE PATH – series of states through which a system passes during a process Melting BASIC CONCEPTS PROCESSES AND CYCLE CYCLE – a system returns to its initial state at the end of the process Melting Freezing BASIC CONCEPTS PROCESSES AND CYCLE Isobaric – constant _________ Isothermal – constant __________ Isochoric – constant ___________ Adiabatic – constant ____________ BASIC CONCEPTS Mass, m = 0.2 kg Volume, v = 0.1 m3 Temperature, T = 298K Pressure, P = 1 atm Density,ρ = 2 kg/m3 Specific volume, υ = 0.5 m3/kg ? BASIC CONCEPTS PROPERTIES Thermodynamics Properties Extensive • value varies directly with mass Intensive • independent of the mass BASIC CONCEPTS Mass, m = 0.2 kg Mass, m = Volume, v = 0.1 m3 Volume, v= Temperature, T = 298K Temperature, T = Pressure, P = 1 atm Pressure, P = Density,ρ = 2 kg/m3 Density,ρ = Specific volume, υ = 0.5 m3/kg Specific volume, υ = BASIC CONCEPTS BASIC PROPERTIES •SI unit: kg •Other units: lbm, metric ton, oz,ton •SI unit: meter •cm, mm, µm, Å, in, ft, yd, mile •SI unit : second •Minute, hour, day •SI unit: Kelvin,K • °C,°F, R BASIC CONCEPTS BASIC PROPERTIES Temperature T(K)=T(°C) +273 T(R)= T(°F)+ 460 T(R)= 1.8 T(K) T(°F) = 1.8 T(°C)+32 BASIC CONCEPTS DERIVED PROPERTIES Force - Unit, N N = force required to accelerate a mass of 1 kg at the rate of 1 meter per second per second BASIC CONCEPTS Determine the weight of a one kg mass at a location where the acceleration of gravity is 9.75 m/s2. Ans: 9.75 N BASIC CONCEPTS DERIVED PROPERTIES Pressure - the force applied to a unit area of surface - SI unit : Pascals (Pa) - kPa, mmHg,bar, torr,dynes/cm2 BASIC CONCEPTS BASIC CONCEPTS DERIVED PROPERTIES Pressure Pabs = Pg + Patm Pvac = Patm - Pabs BASIC CONCEPTS DERIVED PROPERTIES Pressure Pabs = Patm + ρgh BASIC CONCEPTS A manometer is used to measure the pressure in a tank. The fluid used has a specific gravity of 0.85 and the manometer column height is 55 cm. If the local atmospheric pressure is 96 kPa, determine the absolute pressure within the tank. BASIC CONCEPTS DERIVED PROPERTIES Density Mass per unit volume Specific volume Reciprocal of the density BASIC CONCEPTS BASIC CONCEPTS A 5m3 container is filled with 900kg of granite (ρ = 2400 kg/ m3) and the rest of the volume is air with density equal to 1.15 kg/ m3. Find the mass of air and the overall (average) specific volume. BASIC CONCEPTS ENERGY Energy can exist in numerous forms thermal, mechanical, kinetic, potential, electric, magnetic, chemical, nuclear BASIC CONCEPTS ENERGY The sum of all the energies is the total energy,E of the system Total energy, E (kJ) on a mass basis, e (kJ/kg) BASIC CONCEPTS ENERGY Thermodynamics : - deals with change of energy - eg. Falling rock – depends only on elevation difference not on the reference level. BASIC CONCEPTS - A system possesses as a whole with respect to some Macroscopic outside reference frames Energy Kinetic and potential energies - - - Forms of energy related to molecular structure of a system and the degree of Microscopic Energy molecular activity Independent of outside reference frame Total Energy BASIC CONCEPTS ENERGY Kinetic Energy Kinetic energy is the energy of motion. An object which has motion - whether it be vertical or horizontal motion - has kinetic energy. Please ad BASIC CONCEPTS Check Your Understanding Determine the kinetic energy of a 1000-kg roller coaster car that is moving with a speed of 20.0 m/s. BASIC CONCEPTS ENERGY Potential energy The stored energy of position BASIC CONCEPTS Use this principle to determine the blanks in the following diagram. Knowing that the potential energy at the top of the tall platform is 50 J, what is the potential energy at the other positions shown on the stair steps and the incline? BASIC CONCEPTS ENERGY BASIC CONCEPTS ENERGY Internal energy - The sum of all the microscopic forms of energy - Denoted by U BASIC CONCEPTS Total Energy BASIC CONCEPTS A 2200 kg automobile traveling at 25m/s hits the rear of a stationary, 1000 kg automobile. After the collision, the large automobile slows to 13.89 m/s and the smaller vehicle has a speed of 24.44 m/s. What has been the increase in internal energy, taking both vehicles as the system?