Sep 9, 2010 #1 tech2580 Petroleum Sep 9, 2010 1 0 0 US The problem is: A 2ft^3 vessel is filled w/ 1 lbm of water at 100psia. What is the total internal energy and entropy of the vessel? It's been a while since working a problem like this, any ideas? Everything is greatly appreciated, many thanks in advance
The problem is: A 2ft^3 vessel is filled w/ 1 lbm of water at 100psia. What is the total internal energy and entropy of the vessel? It's been a while since working a problem like this, any ideas? Everything is greatly appreciated, many thanks in advance
Sep 9, 2010 1 #2 davefitz Mechanical Jan 27, 2003 2,924 0 0 US you need any 2 properties to determine the other properties. You have P= 100psia, and v= 2./1. = 2 ft3/lbm. so now use a steam table and obtain the rest. Upvote 0 Downvote
you need any 2 properties to determine the other properties. You have P= 100psia, and v= 2./1. = 2 ft3/lbm. so now use a steam table and obtain the rest.
Sep 9, 2010 #3 25362 Chemical Jan 5, 2003 4,826 0 0 CA Since 0.5 lb/cf is not the density of the water at 100 psia, can you tell us the temperature? Upvote 0 Downvote
Sep 10, 2010 #4 davefitz Mechanical Jan 27, 2003 2,924 0 0 US Another word for water that has already evaporated is "steam" from the following online steam tables <http://www.steamtablesonline.com/steam97web.aspx>p=100., T= 327.8, v= 2.0, h= 697.7, s=0.981216 units are english units, not metric. Upvote 0 Downvote
Another word for water that has already evaporated is "steam" from the following online steam tables <http://www.steamtablesonline.com/steam97web.aspx>p=100., T= 327.8, v= 2.0, h= 697.7, s=0.981216 units are english units, not metric.
Sep 10, 2010 #5 ione Mechanical Oct 22, 2009 1,342 0 0 IT From the tables I’ve got at p = 100 psia and T = 327.87 °F the specific volume of steam v = 4.43313 ft3/lb. Upvote 0 Downvote
From the tables I’ve got at p = 100 psia and T = 327.87 °F the specific volume of steam v = 4.43313 ft3/lb.
Sep 10, 2010 #6 25362 Chemical Jan 5, 2003 4,826 0 0 CA My steam tables didn't show a value for the given data. Therefore I had to assume it is a mixture of liquid and vapor. It appears to be wet steam with a 44.9% quality as shown by the "calculator" suggested by davefitz. Upvote 0 Downvote
My steam tables didn't show a value for the given data. Therefore I had to assume it is a mixture of liquid and vapor. It appears to be wet steam with a 44.9% quality as shown by the "calculator" suggested by davefitz.
Sep 10, 2010 #7 ione Mechanical Oct 22, 2009 1,342 0 0 IT 25362, I was referring to dry steam. I agree with you that wet steam (44.9% dryness) has the values of enthalpy reported by davefitz Upvote 0 Downvote
25362, I was referring to dry steam. I agree with you that wet steam (44.9% dryness) has the values of enthalpy reported by davefitz
Sep 10, 2010 #8 gruntguru Mechanical Mar 1, 2008 1,247 0 36 AU At the given pressure and specific volume it cannot be "dry steam". It is a "saturated mixture" Upvote 0 Downvote
Sep 10, 2010 #9 25362 Chemical Jan 5, 2003 4,826 0 0 CA One exception to the statement: You need any 2 properties to determine the other properties. Click to expand... It cannot apply when the two given properties are saturation pressure and temperature. In this case one needs an extensive property. Upvote 0 Downvote
One exception to the statement: You need any 2 properties to determine the other properties. Click to expand... It cannot apply when the two given properties are saturation pressure and temperature. In this case one needs an extensive property.
Sep 10, 2010 #10 25362 Chemical Jan 5, 2003 4,826 0 0 CA Or, of course, the steam quality. Upvote 0 Downvote
Sep 10, 2010 #11 25362 Chemical Jan 5, 2003 4,826 0 0 CA Or specific volume, which is another intensive property. Upvote 0 Downvote