How Does Adding Heat Affect Pressure in a Sealed Steam Container?

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SUMMARY

The discussion focuses on the thermodynamic analysis of a sealed steam container subjected to heat addition. Initial conditions include a temperature of 200°C, mass of 10 kg, and volume of 1 m³, resulting in an initial pressure of 1554.9 KPa. After heating to 350°C, the final pressure is calculated to be 16529 KPa. Key calculations reveal that no work is performed (W = 0) and the change in internal energy (Δu) amounts to 1759 kJ, derived from the difference in internal energy values obtained from thermodynamic tables.

PREREQUISITES
  • Understanding of thermodynamic principles, specifically the first law of thermodynamics.
  • Familiarity with steam tables for saturated vapor systems.
  • Knowledge of specific volume calculations in thermodynamics.
  • Ability to perform energy balance calculations in closed systems.
NEXT STEPS
  • Study the first law of thermodynamics in detail, focusing on closed systems.
  • Learn how to effectively use steam tables for various thermodynamic properties.
  • Research specific volume calculations and their applications in thermodynamic analysis.
  • Explore the concept of quality in steam and its significance in phase change processes.
USEFUL FOR

This discussion is beneficial for students and professionals in mechanical engineering, particularly those specializing in thermodynamics, steam systems, and energy analysis.

TheBelgiumWaff
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1. Homework Statement

Given: A sealed, rigid container (cannot change shape or size) containing steam at the shown conditions has heat added until it reaches the final shown state.

Determine: a) heat added, b) work performed, c) change in internal energy of the system, and d) final system pressure

2. Homework Equations

Q = W + Δu

Also given: T1= 200 deg C, mass = 10kg, volume = 1m^3 (for initial conditions)
T2 = 350 C (for final conditions)

The pressures I found in the thermo tables for the corresponding temperatures are:
P1 = 1554.9 KPa
P2 = 16529 KPa

3. The Attempt at a Solution

What I know is it's a saturated vapor system since it stated steam in the problem statement and closed system so no work is done.

From that I was able to answer b) W = 0 and c) Q = 0 + m(u1-u2) --> 10Kg(2594.2-2418.3) KJ/kg = 1759 KJ of internal energy. The u's I got from thermo tables.

The two I'm having a hard time with is a) the heat added to the system and d) final system pressure.
 
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You already found the answer to a. Look at what you put for c. You also already found the final pressure.
 
Also I can tell the quality is not going to be 100%. You can use the volume and mass to find the specific volume. Than use that specific volume and the specific volumes from the table for state 1 and 2 to find the quality.
 

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