Matt's Question: Heat Transfer and Entropy Change for H2/N2 Mixture

Click For Summary
SUMMARY

The discussion centers on calculating heat transfer and entropy change for a mixture of 0.2 kg of hydrogen (H2) and 1.6 kg of nitrogen (N2) at a pressure of 100 kPa and a temperature of 300 K. The heat transfer is determined using the equation mCΔT, yielding an approximate value of 29 kJ. However, the user mistakenly considers flow rate and specific humidity as relevant factors, which are not applicable in this context. The focus should remain on constant pressure conditions and the specific heats of the gases involved.

PREREQUISITES
  • Understanding of thermodynamics principles, specifically heat transfer.
  • Familiarity with the ideal gas law and its application to mixtures.
  • Knowledge of specific heats for H2 and N2 at varying temperatures.
  • Ability to perform calculations involving mass, specific heat, and temperature change.
NEXT STEPS
  • Review the concept of constant pressure heat transfer in thermodynamic systems.
  • Study the specific heat capacities of hydrogen and nitrogen at different temperatures.
  • Learn about entropy change calculations for gas mixtures.
  • Explore the ideal gas law and its implications for non-ideal mixtures.
USEFUL FOR

Students and professionals in thermodynamics, mechanical engineers, and anyone involved in heat transfer analysis of gas mixtures.

Synergyx 26
Messages
4
Reaction score
0
Hey everyone, I'm new to the forums here and just have a question.

Homework Statement


A piston-cylinder device contains a mixture of .2kg of H2 and 1.6kg of N2 at 100kPa and 300K. Heat is now transferred to the mixture at constant pressure until the volume is doubled. Assuming constant specific heats at the average temperature, determine (a) the heat transfer and (b) the entropy change of the mixture

The Attempt at a Solution


My multiple attempts included using equations from examples in the chapter. The only thing with the example is that its with air and not H2 or N2. I don't know if this really makes a difference but I've tried m C deltaT to find the heat and gotten an answer of around 29kJ but my understanding of the problem is that I'm looking for the flow of the heat transfer in kJ/min which involves using the partial pressure and specific humidity. The main thing I'm lacking in that process is the I have no flow in kg/min. Any help would be much appreciated.

Matt
 
Physics news on Phys.org
Hi Synergyx 26, welcome to PF. Please show your calculations if you'd like others to comment; right now there's no way to know what you've tried.

What assumptions can you make about the gases involved that might help you to extract a temperature change?

Humidity and flow are not relevant factors in this problem.
 

Similar threads

Flow inside pipe, heat transfer
  • · Replies 15 ·
Replies
15
Views
3K
Thermodynamics (Entropy Generation and Heat Engine)
  • · Replies 3 ·
Replies
3
Views
4K
Find entropy change when two tanks equalize
  • · Replies 4 ·
Replies
4
Views
4K
Design of a Double Pipe Heat Exchanger
  • · Replies 12 ·
Replies
12
Views
4K
Thermodynamics Energy transfer question
  • · Replies 10 ·
Replies
10
Views
2K
Solve Heat Transfer Homework: Find Constant K in kW/min
  • · Replies 2 ·
Replies
2
Views
3K
Figuring Out Heat Transfer & Entropy of Steam at 10 MPa
  • · Replies 2 ·
Replies
2
Views
2K
Estimate the local heat transfer flux
  • · Replies 16 ·
Replies
16
Views
4K
Graduate Practical use of an overall heat transfer coefficient?
  • · Replies 14 ·
Replies
14
Views
3K
Well insulated tank with valve entropy problem
  • · Replies 3 ·
Replies
3
Views
3K