The temperature entropy diagram for helium-4 is shown in Fig. 2. For this question, an accuracy of half of the grid inte

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The Temperature Entropy Diagram For Helium 4 Is Shown In Fig 2 For This Question An Accuracy Of Half Of The Grid Inte 1 (130.54 KiB) Viewed 54 times

The temperature entropy diagram for helium-4 is shown in Fig. 2. For this question, an accuracy of half of the grid interval is sufficient when reading numerical values from the diagram (a) Helium gas at initial pressure and temperature P20 atm and T; -15K expends by the Joule-Thomson process through a throttling valve. Use the diagram to estimate the final temperature if the final pressure Platm. (b) Use the diagram to estimate the maximal initial temperature for which it would be possible to produce liquid He. Then estimate the molar enthalpy of He-gas at 1 atm pressure and in equilibrium with liquid He. (c) Helium gas at P10 atm and T; 6.8K is pushed through a throttling valve where the pressure drops to Pe = 1 atm. Estimate the percentage of helium gas which will be converted into liquid. 2 20 2530 solo VI TIT RS.CO 60 26 DOO 125 200 30000 GOO 16 23 22 14 20, Colom 419 - Page 22. -14 03 IN 3 Saturated So 4 Saturated Liquid for Vepariation Lambda Transition 3 wo OS 5 Saturated Liquid for Selidification os ali Oi 02 03 04 05 06 07 ENTROPY, (color) 20 30 ENTROPY, (cal/gmk) 50 C-3891 Figure 5. Temperature Entropy Diagram of Helium Figure 2: Temperature - entropy diagram for helium-4. Both liquid and gas phases of He coexist in the two-phase region (the region below the dashed line). Note that the units of energy are calories (1 cal = 4.19 J). The diagram shows constant pressure (atm, solid lines), constant specific volume (liters/kg, dashed), and constant specific enthalpy (cal/g, solid) lines.