[Thermodynamics I] Adding heat to a closed, rigid tank

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SUMMARY

The discussion focuses on a thermodynamics problem involving a closed, rigid tank containing 2 kg of water at an initial temperature of 80 degrees Celsius and a quality of 0.6. The objective is to determine the energy transfer by heat until the tank reaches a saturated vapor state. Key equations utilized include U = Q - W, with W being zero, leading to U = Q, and the use of steam tables to find specific internal energy values for both water and vapor. The solution involves calculating initial and final states using the steam tables to determine enthalpy and volume at the specified conditions.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically the first law of thermodynamics.
  • Familiarity with steam tables for water and vapor properties.
  • Knowledge of specific internal energy and enthalpy calculations.
  • Concept of quality in thermodynamics and its implications in phase changes.
NEXT STEPS
  • Study the use of steam tables for calculating properties of water and steam at various temperatures and pressures.
  • Learn about the first law of thermodynamics and its application in closed systems.
  • Explore the concept of quality and its role in phase transitions in thermodynamic systems.
  • Investigate interpolation techniques for determining properties between tabulated values in steam tables.
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Students and professionals in mechanical engineering, particularly those specializing in thermodynamics, as well as anyone involved in heat transfer analysis and energy calculations in closed systems.

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Homework Statement


A closed, rigid tank contains 2kg of water initially at 80 degrees C and a quality of .6. Heat transfer occurs until the tank contains only saturated vapor at a higher pressure. Kinetic and potential energy effects are negligible. For the water as the system, determine the amount of energy transfer by heat, in kJ.


Homework Equations


U = Q - W, W = 0 => U = Q
mu = U
pv = RT

The Attempt at a Solution


I don't really know where to even begin. I know the volume is constant, and I assume that I need to find the specific internal energy for the water and water vapor at the initial and final temperatures. Given the initial temperature and knowing V is constant, I might be able to determine pressure? I can't figure out how I would find the temperature and pressure for the saturated water vapor state either.
 
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hi, the question has given mass as 2kg, this helps in finding results from the sp. volume/sp.enthalpy from the steam tables..at 80C find hf & hg and similarly for sp.volume along with the quality, find the total enthalpy and volume at 80C, then, since, its a closed tank, the volume of matter remains the same but changes from liquid-vapour mixture to vapour condition. At, sat. vapour condition, only vapour remains but the volume remains the same which was found at 80C and with this volume, using steam tables look to match identical volumes in the superheated steam tables-might require interpolation..
 
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