Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Homework Help
Engineering and Comp Sci Homework Help
Finding Minimum Work to Compress Water
Reply to thread
Message
[QUOTE="megisacat, post: 5455946, member: 591744"] [h2]Homework Statement [/h2] Find the minimum work to compress 1 kg of water isothermally from p1=1 bar, T1=120C to a volume that is 1/3 the original volume. [h2]Homework Equations[/h2] Energy balance Q-W=U+KE+PE [h2]The Attempt at a Solution[/h2] So first I found the phase of the water (p<psat for that temp so superheated vapor) I found the properties (v,u,h,s) for that temperature and pressure in the superheated table. I can use the specific volume at 1 to find the specific volume at 2 because mass stays constant (closed system) and it's just 1/3 v1. I used that specific volume to determine the state at 2 (in between vf and vg so it's in the saturated liquid vapor phase). I found the quality using tables so I can calculate u, h, s. I'm mostly confused about the energy balance: I'm pretty sure I can neglect KE and PE. Is there a Q value though? When I went over this problem with the professor he hinted at using TdS equations (Gibbs?) for finding the heat. The Tds equation that I know is Tds=du+Pdv (which is similar to the energy balance since Pdv is the work and du is the the change in internal energy). Do I do W=du+Tds? Or maybe it is okay to just assume no heat transfer and do W=U and then do m(u2-u1). I'm mostly confused about when you can assume things when doing energy balance. [/QUOTE]
Insert quotes…
Post reply
Forums
Homework Help
Engineering and Comp Sci Homework Help
Finding Minimum Work to Compress Water
Back
Top