Thermodynamics

cen84959_ch03.qxd 4/1/05 12:31 PM Page 163of refrigerant-134a that is a saturated liquid at 0.8 MPa, whilethe other side is evacuated. The partition is now removed,and the refrigerant fills the entire tank. If the final state of therefrigerant is 20°C and 400 kPa, determine the volume of thetank.R-134aV = 0.01 m 3P = 0.8 MPaEvacuatedFIGURE P3–1263–127 Reconsider Prob. 3–126. Using EES (or other)software, investigate the effect of the initialpressure of refrigerant-134a on the volume of the tank.Let the initial pressure vary from 0.5 to 1.5 MPa. Plot thevolume of the tank versus the initial pressure, and discussthe results.3–128 Liquid propane is commonly used as a fuel for heatinghomes, powering vehicles such as forklifts, and fillingportable picnic tanks. Consider a propane tank that initiallycontains 5 L of liquid propane at the environment temperatureof 20°C. If a hole develops in the connecting tube of apropane tank and the propane starts to leak out, determine thetemperature of propane when the pressure in the tank dropsto 1 atm. Also, determine the total amount of heat transferfrom the environment to the tank to vaporize the entirepropane in the tank.LeakFIGURE P3–128Propane3–129 Repeat Prob. 3–128 for isobutane.3–130 A tank contains helium at 100°C and 10 kPa gage.The helium is heated in a process by heat transfer from thesurroundings such that the helium reaches a final equilibriumstate at 300°C. Determine the final gage pressure of thehelium. Assume atmospheric pressure is 100 kPa.Chapter 3 | 1633–13l A tank contains argon at 600°C and 200 kPa gage.The argon is cooled in a process by heat transfer to the surroundingssuch that the argon reaches a final equilibriumstate at 300°C. Determine the final gage pressure of theargon. Assume atmospheric pressure is 100 kPa.3–132 Complete the blank cells in the following table ofproperties of steam. In the last column describe the conditionof steam as compressed liquid, saturated mixture, superheatedvapor, or insufficient information; and, if applicable,give the quality.Condition descriptionP, kPa T, °C v, m 3 /kg u, kJ/kg and quality (if applicable)200 30270.3 130400 1.5493300 0.500500 30843–133 Complete the blank cells in the following table ofproperties of refrigerant-134a. In the last column describe thecondition of refrigerant-134a as compressed liquid, saturatedmixture, superheated vapor, or insufficient information; and,if applicable, give the quality.Condition descriptionP, kPa T, °C v, m 3 /kg u, kJ/kg and quality (if applicable)320 121000 39.3740 0.17794180 0.0700200 2493–134 On the property diagrams indicated below, sketch(not to scale) with respect to the saturated liquid and saturatedvapor lines and label the following processes and statesfor refrigerant-134a. Use arrows to indicate the direction ofthe process, and label the initial and final states:(a) On the P-v diagram sketch the constant temperatureprocess through the state P 280 kPa, v 0.06 m 3 /kg aspressure changes from P 1 400 kPa to P 2 200 kPa.Place the value of the temperature on the process curve onthe P-v diagram.(b) On the T-v diagram sketch the constant specific volumeprocess through the state T 20°C, v 0.02 m 3 /kg fromP 1 1200 kPa to P 2 300 kPa. For this data set place thetemperature values at states 1 and 2 on its axis. Place thevalue of the specific volume on its axis.