View by Category

The presentation will start after a short

(15 second) video ad from one of our sponsors.

Hot tip: Video ads won’t appear to registered users who are logged in. And it’s free to register and free to log in!

(15 second) video ad from one of our sponsors.

Hot tip: Video ads won’t appear to registered users who are logged in. And it’s free to register and free to log in!

Loading...

PPT – 1' Thermodynamic Systems: Definitions PowerPoint presentation | free to download - id: 21c36d-NTUyO

The Adobe Flash plugin is needed to view this content

About This Presentation

Write a Comment

User Comments (0)

Transcript and Presenter's Notes

1. Thermodynamic Systems Definitions

- Purpose of this lecture
- To refresh your memory about some major

concepts, definitions, and thermodynamic property

relations that we will be using in CHEE 311 - Learning objectives
- To be able to distinguish between isolated,

closed, and open systems - To understand the definition of intensive and

extensive variables - How the fundamental equation for closed systems

is being derived from the 1st and 2nd Laws of

Thermodynamics - To be able to derive the property relations for

H, G, A - Reading assignment Chapter 6.1 from the textbook

Thermodynamic Systems Definitions

- The first step in all problems in thermodynamics

is to define a system, either a body or a defined

region of space. - Types of Systems
- Isolated no transfer of energy or matter across

the system boundaries - Closed possible energy exchange with the

environment but no transfer of matter - Open exchange of energy and matter with the

environment - Phase part of a system that is spatially

uniform in its properties (density,

composition,...)

Thermodynamic Properties

- Thermodynamics is concerned with macroscopic

properties of a body, not atomic properties - Volume, surface tension, viscosity, etc
- Divided into two classes
- Intensive Properties (density, pressure,)
- specified at each point in the system
- spatially uniform at equilibrium
- Usually, specifying any 2 intensive variables

defines the values of all other intensive

variables - Ij f(I1, I2) (j3,4,5,,n)
- This holds for mixtures as well, but composition

must also be defined - Ij f(I1, I2, x1,x2,,xm-1) (j3,4,5,,n)
- for an m-component mixture.

Thermodynamic Properties

- Extensive Properties (volume, internal

energy,...) - Additive properties, in that the system property

is the sum of the values of the constituent parts - Usually, specifying any 2 intensive and one

extensive (conveniently the system mass) defines

the values of all other extensive variables - Ej m f(I1, I2, x1,x2,,xm-1) (j3,4,5,,n

) - for an m-component mixture.
- The quotient Ei / m (molar volume, molar Gibbs

energy) is an intensive variable, often called a

specific property

2. The Fundamental Equation

- Closed Systems
- We require numerical values for thermodynamic

properties to calculate heat and work (and later

composition) effects - Combining the 1st and 2nd Laws leads to a

fundamental equation relating measurable

quantities (PVT, Cp, etc) to thermodynamic

properties (U,S) - Consider n moles of a fluid in a closed system
- If we carry out a given process, how do the

system properties change? - 1st law
- dnU dQ dW
- when a reversible volume change against an

external pressure is the only form of work - dWrev - P dnV (1.2)

The Fundamental Equation

- When a process is conducted reversibly, the 2nd

law gives - dQrev T dnS (5.12)
- Therefore, for a reversible process wherein only

PV work is expended, - dnU T dnS - P dnV (6.1)
- This is the fundamental equation for a closed

system - must be satisfied for any change a closed system

undergoes as it shifts from one equilibrium state

to another - defined on the basis of a reversible process,

does it apply to irreversible (real-world)

processes?

Fundamental Eqn and Irreversible Processes

- The fundamental equation
- dnU T dnS - P dnV
- applies to closed systems shifting from one

equilibrium state to another, irrespective of

path. - Note that the terms TdnS and PdnV can be

identified with the heat absorbed and work

expended only for the reversible path. - dQ dW dnU TdnS - PdnV
- whenever we have an irreversible process (AB),

we find - dQ lt TdnS AND dW lt PdnV
- the sum yields the expected change of dnU
- Given our focus on fluid phase equilibrium, the

lost ability to interpret the meaning of TdnS and

PdnV is of secondary importance.

Auxiliary Functions

- The whole of the physical knowledge of

thermodynamics (for closed systems) is embodied

in P,V,T,U,S as related by the fundamental

equation, 6.1 - IT IS ONLY A MATTER OF CONVENIENCE that we

define auxiliary functions of these primary

thermodynamic properties. - Enthalpy H º U PV 2.11
- Helmholtz Energy A º U - TS 6.2
- Gibbs Energy G º H - TS 6.3
- U PV - TS
- All of these quantities are combinations of

previous functions of state and are therefore

state functions as well. - Their utility depends on the particular system

and process under investigation

Differential Expressions for Auxiliary Properties

- The auxiliary equations, when differentiated,

generate more useful property relationships - dnU TdnS - PdnV U(S,V)
- dnH TdnS nVdP H(S,P)
- dnA -PdnV - nSdT A(V,T)
- dnG nVdP - nSdT G(P,T) (6.7-6.10)
- Given that pressure and temperature are process

factors under our control, Gibbs energy is

particularly well suited to fluid phase

equilibrium design problems.

3. Defining Maxwells Equations

- Purpose of this lecture
- Introduction into the Maxwells equations
- Learning objectives
- To understand and apply the criterion of

exactness to fundamental property relations - To understand where and how Maxwells relations

are useful - To achieve competence in deriving and applying

the Maxwells equations toward the calculation of

thermodynamic property changes - Reading assignment Chapter 6.1 from the textbook

Defining Maxwells Equations

- The fundamental equations can be expressed as
- from which the following relationships are

derived

Maxwells Equations

- The fundamental property relations are exact

differentials, meaning that for - defined as
- 6.11
- then we have,
- 6.12
- When applied to equations 6.7-6.10 for molar

properties, we derive Maxwells relations - 6.13-6.16

Maxwells Equations - Example 1

- We can immediately apply Maxwells relations to

derive quantities that we require in later

lectures. These are the influence of T and P on

enthalpy and entropy. - Enthalpy Dependence on T,P-closed system
- Given that HH(T,P)
- The final expression, including the pressure

dependence is - 6.20
- Which for an ideal gas reduces to
- 6.23

Maxwells Equations - Example 2

- Entropy Dependence on T,P-closed system
- Given that SS(T,P)
- The final expression, including the pressure

dependence is - 6.21
- Which for an ideal gas reduces to
- 6.24

Example 3

SVNA 6.21 - The state of 1(lbm) of steam is

changed from saturated vapour at 20 psia to

superheated vapour at 50 psia and 1000?F. (a)

What are the enthalpy and entropy changes of the

steam? (b) What would the enthalpy and entropy

changes be if steam were an ideal gas?

Properties from Steam Tables (SVNA)

Answers (a)

(b)

About PowerShow.com

PowerShow.com is a leading presentation/slideshow sharing website. Whether your application is business, how-to, education, medicine, school, church, sales, marketing, online training or just for fun, PowerShow.com is a great resource. And, best of all, most of its cool features are free and easy to use.

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

You can use PowerShow.com to find and download example online PowerPoint ppt presentations on just about any topic you can imagine so you can learn how to improve your own slides and presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

presentations for free. Or use it to find and download high-quality how-to PowerPoint ppt presentations with illustrated or animated slides that will teach you how to do something new, also for free. Or use it to upload your own PowerPoint slides so you can share them with your teachers, class, students, bosses, employees, customers, potential investors or the world. Or use it to create really cool photo slideshows - with 2D and 3D transitions, animation, and your choice of music - that you can share with your Facebook friends or Google+ circles. That's all free as well!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

For a small fee you can get the industry's best online privacy or publicly promote your presentations and slide shows with top rankings. But aside from that it's free. We'll even convert your presentations and slide shows into the universal Flash format with all their original multimedia glory, including animation, 2D and 3D transition effects, embedded music or other audio, or even video embedded in slides. All for free. Most of the presentations and slideshows on PowerShow.com are free to view, many are even free to download. (You can choose whether to allow people to download your original PowerPoint presentations and photo slideshows for a fee or free or not at all.) Check out PowerShow.com today - for FREE. There is truly something for everyone!

Recommended

«

/ »

Page of

«

/ »

Promoted Presentations

Related Presentations

Page of

Page of

CrystalGraphics Sales Tel: (800) 394-0700 x 1 or Send an email

Home About Us Terms and Conditions Privacy Policy Contact Us Send Us Feedback

Copyright 2016 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

Copyright 2016 CrystalGraphics, Inc. — All rights Reserved. PowerShow.com is a trademark of CrystalGraphics, Inc.

The PowerPoint PPT presentation: "1' Thermodynamic Systems: Definitions" is the property of its rightful owner.

Do you have PowerPoint slides to share? If so, share your PPT presentation slides online with PowerShow.com. It's FREE!