@@lecturesandlearningchannel6605 can you do a vid (if not already) on how fugacity plays into all this? Your enthalpy distinction was one of the best I've seen. Fugacity is another concept I struggle to truly internalize. I work with butanes/propane liquids/vapors more than h20 steam
Thank you for the video. I know this can be confusing, and quality/enthalpy of wet steam is sometimes a question that comes up on state exams. Below I will do my best to explain it and show the calculations. The reference for this is Steam Power Engineering Third Edition, by Edgar MacNaughton, pg. 65-69. Steam quality or enthalpy of wet steam is a fourth value that can be determined if three sets of values are known. There are two calculations for this. The first calculation is the same as the one shown in the video and uses the quality percentage to determine the enthalpy of the wet steam. The second calculation determines the quality percentage of the steam using the enthalpy of the wet steam. I'm going to use the same numbers as he used in the video and show both calculations except that I use a q to represent quality. He also used hTot to represent wet steam. Here I use hs which represents heat of steam. hs = hf + q(hfg) q=(hs-hf)/hfg q = Percentage of quality/dry fraction = 50%, hs = Enthalpy of wet steam 869.5 Btu/lb, hf = enthalpy of saturated liquid = 548 Btu/lb, hfg = enthalpy of evaporation = 643 Btu/lb, hg = hf + hfg 1191 Btu/lb The first calculation is the same as in the video except I use a q to represent quality. hs = hf + q(hfg)→ hs = 548 + 0.5(643) → hs = 548 + 321.5→ hs = 869.5 Btu/lb This calculation uses the enthalpy of wet steam to determine the quality/dryness fraction. q=(hs-hf)/hfg → q=(896.5-548)/643 →q=321.5/643 = 0.5, Quality = 50% I'll put a couple of different word problems below using the formulas. A pound of wet steam at 600 psia has 90% quality. What is the enthalpy of the steam? Use steam tables: Find values for saturated steam at 600psia. hf (saturated liquid) = 471.6, hfg (latent heat of evaporation) = 731.6, hg (saturated vapor hf+hfg) =1203.2 hs = hf + q(hfg)→ hs = 471.6 + 0.9(731.6) → hs = 471.6 + 658.4 → hs=1130.04 A pound of wet steam at 600psia has an enthalpy of 1130 Btu/lb, what is the percentage of quality? Use steam tables: Find values for 600psia. hf (saturated liquid) = 471.6, hfg (latent heat of evaporation) = 731.6, hg (saturated vapor hf+hfg) =1203.2 q=(hs-hf)/hfg → q=(1130-471.6)/731.6 → q=(658.4)/731.6→ 0.8999, 90% quality
Ok but how do you know what X is? X also represents the amount of latent energy that has been added but if the pressure and temp remain constant until you reach full saturation, how do determine X?
In calculations X is the unknown value that needs to be determined. I added a detailed comment to this video that explains the calculation used in this video and how to determine the percentage of quality. I also included a couple of word problems to help further show how these calculation are done. I hope the comment I added to this video will help you understand the math. 😊
Side Note, The reason you don't use water is that water would require a pump. A pump requires electricity. Using electricity to generate electricity........ 😂
These vids are great! Thank you!!
Glad you like them.
@@lecturesandlearningchannel6605 can you do a vid (if not already) on how fugacity plays into all this? Your enthalpy distinction was one of the best I've seen. Fugacity is another concept I struggle to truly internalize. I work with butanes/propane liquids/vapors more than h20 steam
Thank you for the video. I know this can be confusing, and quality/enthalpy of wet steam is sometimes a question that comes up on state exams. Below I will do my best to explain it and show the calculations. The reference for this is Steam Power Engineering Third Edition, by Edgar MacNaughton, pg. 65-69.
Steam quality or enthalpy of wet steam is a fourth value that can be determined if three sets of values are known. There are two calculations for this. The first calculation is the same as the one shown in the video and uses the quality percentage to determine the enthalpy of the wet steam. The second calculation determines the quality percentage of the steam using the enthalpy of the wet steam. I'm going to use the same numbers as he used in the video and show both calculations except that I use a q to represent quality. He also used hTot to represent wet steam. Here I use hs which represents heat of steam.
hs = hf + q(hfg) q=(hs-hf)/hfg
q = Percentage of quality/dry fraction = 50%, hs = Enthalpy of wet steam 869.5 Btu/lb, hf = enthalpy of saturated liquid = 548 Btu/lb, hfg = enthalpy of evaporation = 643 Btu/lb, hg = hf + hfg 1191 Btu/lb
The first calculation is the same as in the video except I use a q to represent quality.
hs = hf + q(hfg)→ hs = 548 + 0.5(643) → hs = 548 + 321.5→ hs = 869.5 Btu/lb
This calculation uses the enthalpy of wet steam to determine the quality/dryness fraction.
q=(hs-hf)/hfg → q=(896.5-548)/643 →q=321.5/643 = 0.5, Quality = 50%
I'll put a couple of different word problems below using the formulas.
A pound of wet steam at 600 psia has 90% quality. What is the enthalpy of the steam?
Use steam tables: Find values for saturated steam at 600psia.
hf (saturated liquid) = 471.6, hfg (latent heat of evaporation) = 731.6, hg (saturated vapor hf+hfg) =1203.2
hs = hf + q(hfg)→ hs = 471.6 + 0.9(731.6) → hs = 471.6 + 658.4 → hs=1130.04
A pound of wet steam at 600psia has an enthalpy of 1130 Btu/lb, what is the percentage of quality?
Use steam tables: Find values for 600psia.
hf (saturated liquid) = 471.6, hfg (latent heat of evaporation) = 731.6, hg (saturated vapor hf+hfg) =1203.2
q=(hs-hf)/hfg → q=(1130-471.6)/731.6 → q=(658.4)/731.6→ 0.8999, 90% quality
Super helpful!!!
Ok but how do you know what X is? X also represents the amount of latent energy that has been added but if the pressure and temp remain constant until you reach full saturation, how do determine X?
In calculations X is the unknown value that needs to be determined. I added a detailed comment to this video that explains the calculation used in this video and how to determine the percentage of quality. I also included a couple of word problems to help further show how these calculation are done. I hope the comment I added to this video will help you understand the math. 😊
My man .. you always lit 🔥
Thank you
How do you maintain a constant pressure in a steam drum?
Could u please clarify this confusion
Thank u
Thanks!
Side Note, The reason you don't use water is that water would require a pump. A pump requires electricity. Using electricity to generate electricity........ 😂
Yeah, we aren't really using heat, we are using heat to create a vapor under pressure to perform mechanical work. 😄
Non of these guys work in a plant