VEERAYATAN INSTITUTE OF ENGINEERING RESEARCH & TECHNOLOGY PowerPoint Presentation of Engineering Thermodynamic Branch – Mechanical Sem – 3rd Group - 1

Bhatt Dharmang Bhatt Milan Bhimani Vishal Bhogayata Nikunj Chamar Pavan Chaudhari Pranav

BASIC CONCEPTS OF THERMODYNAMICS

TOPIC OF UNIT Microscopic & Macroscopic point of view Microscopic & Macroscopic point of view Thermodynamic system and control volume Thermodynamic system and control volume Thermodynamic properties, processes and cycles Thermodynamic properties, processes and cycles Thermodynamic equilibrium Thermodynamic equilibrium Quasi-static process Quasi-static process

A collection of atoms within a container, each with a unique velocity. MICROSCOPIC AND MACROSCOPIC POINT OF VIEW

Energy in a microscopic description Number of atoms = N Energy of each atom = Total Energy =

The macroscopic description The energy in both cases is the same, E. In the macroscopic description, atomistic concepts are disregarded. How we describe the system chosen for study requires careful selection of properties that are based on observable, measurable quantities.

THERMODYNAMIC SYSTEM AND CONTROL VOLUME Thermodynamic system or system : It is defined as a quantity of matter or a region in space chosen for study Thermodynamic system or system : It is defined as a quantity of matter or a region in space chosen for study Surrounding or environment : It is the matter or region outside the system Surrounding or environment : It is the matter or region outside the system Universe : The combination of system and the surroundings together is usually refered to as the universe Universe : The combination of system and the surroundings together is usually refered to as the universe

Energetic interactions Surroundings Energy Flow System Boundary

Closed System In this system no mass transfer across the system boundary. But energy, in form of heat or work, can cross the boundary. m Gas at pressure, p Piston

Open System In this system the mass as well as energy transfer across the boundary of system Shaft Work Output Combustor Fuel Flow In Air Flow In Exhaust Gases Out Compressor Work Out

Isolated System In this system, fixed mass and fixed energy, and there is no mass or energy transfer across the system boundary. The thermos flask is example of isolated system No energy transfer No mass transfer Isolated system

Control Volume In most of engineering problems of open system such as in an engine, an air compressor, turbine etc, the mass of the system is not fixed. Therefore, in the analysis, attention is focussed on a certain volume in space surrounding the system, known as the Control volume.

THERMODYNAMIC PROPERTIES Properties: Temperature Pressure Volume Internal energy Entropy Properties: Temperature Pressure Volume Internal energy Entropy System The system can be either open or closed. The concept of a property still applies.

Classes of properties ExtensiveExtensive –MASS –VOLUME –ENERGY ADDITIVE OVER ADDITIVE OVER THE SYSTEM. IntensiveIntensive –TEMPERATUR E –PRESSURE –DENSITY NOT ADDITIVE OVER THE SYSTEM. NOT ADDITIVE OVER THE SYSTEM. Continuum approach is valid if system is large compared to distance between molecules

State, Process, Cycle State : It is the condition of the system at an instant of time as described by its properties. Process : Any change that a system undergoes from one state to another state is called a process. Cycle : It is defined as a series of state change such that the final state is identical with the initial state.

THERMODYNAMICS EQUILIBRIUM Thermodynamics deals with equilibrium states.Thermodynamics deals with equilibrium states. No driving forcesNo driving forces Mechanical equilibriumMechanical equilibrium –No change in pressure with time Thermal equilibriumThermal equilibrium –Temperature is same throughout system Chemical equilibriumChemical equilibrium –Chemical composition does not change with time.

QUASI-STATIC PROCESS When process proceeds in such way that the system remains close to an thermodynamic equilibrium state at all times, it is called a quasi- static process. When process proceeds in such way that the system remains close to an thermodynamic equilibrium state at all times, it is called a quasi- static process. This process is also called a reversible process. This process is also called a reversible process.

Non-Quasi static process Quasi-static process

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