ME 3: Thermodynamics

Proof required

Link the public repo with the odd-numbered problems of chapters 1–3 of the OpenStax physics text (Volume 2), then the first-law examples in the 16 Unified notes written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Each problem draws the system boundary and states what crosses it.
• Sign conventions for work and heat are stated and kept.
• Answers match the chapter keys, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of the odd-numbered problems of chapters 1–3 of the OpenStax physics text (Volume 2), then the first-law examples in the 16 Unified notes, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 3: Thermodynamics, unit 1: Properties, energy and the first law
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Each problem draws the system boundary and states what crosses it.
• Sign conventions for work and heat are stated and kept.
• Answers match the chapter keys, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with the odd-numbered problems of chapter 4 of the OpenStax physics text (Volume 2), then the entropy examples in the 16 Unified notes written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Entropy changes are found along a reversible path between the same states.
• Every efficiency is checked against the Carnot limit.
• Answers match the chapter 4 key, and misses are reworked.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of the odd-numbered problems of chapter 4 of the OpenStax physics text (Volume 2), then the entropy examples in the 16 Unified notes, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 3: Thermodynamics, unit 2: Entropy and the second law
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Entropy changes are found along a reversible path between the same states.
• Every efficiency is checked against the Carnot limit.
• Answers match the chapter 4 key, and misses are reworked.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with Rankine, Brayton and vapour-compression cycle problems from the 16 Unified notes and the NPTEL weekly exercises, solved by hand with steam and refrigerant tables written up (a typeset PDF, LaTeX source or notebook), and show the self-check: which answers matched and how you fixed the ones that did not.

What gets checked

• Each cycle is drawn on a T–s diagram with every state numbered.
• Every hand-calculated state property is checked against CoolProp, and the two agree.
• Net work, heat input and efficiency (or COP) close an energy balance.

Common mistakes

• Answers copied from a solution with no working.
• Missing units, or a free-body diagram or sign convention left out.

Powstik Guide

A public write-up of Rankine, Brayton and vapour-compression cycle problems from the 16 Unified notes and the NPTEL weekly exercises, solved by hand with steam and refrigerant tables, with the self-check shown.

Steps

1. Study the linked course material.
2. Solve the problems on your own first.
3. Check them against the self-check and rework the misses.
4. Typeset the write-up (LaTeX or a notebook) in a public repo.
5. Ask someone who knows the subject to check it.

README
ME 3: Thermodynamics, unit 3: Power and refrigeration cycles
Problems:
Self-check result (matched / reworked):
What I got wrong first and why:

What gets sent back

• No working shown.
• The self-check result is missing.

Resources

What a verifier looks for

• Each cycle is drawn on a T–s diagram with every state numbered.
• Every hand-calculated state property is checked against CoolProp, and the two agree.
• Net work, heat input and efficiency (or COP) close an energy balance.
• Is the engineering right, not just the final number?

You'll sign in first, then come straight back here.

Proof required

Link the public repo with the code or model files, the one command that reruns it, the convergence (mesh or step-size) study and the hand-calculation check, and a README that says how to rerun it and what limits the result.

What gets checked

• The hand calculation and the code agree within 1% for the ideal cycle, shown in a table with every state.
• The sweep plots efficiency and turbine exit quality, with units and the efficiencies used stated.
• The write-up explains the trade-off and checks one point against an energy balance.

Common mistakes

• A result that nobody else can rerun from the repo.
• A table with no explanation of the gaps.

Powstik Guide

A notebook that models a Rankine steam cycle with CoolProp: first ideal, then with real turbine and pump efficiencies, in a public repo.

Steps

1. Write down what you expect before you start.
2. Fix the turbine inlet at 500 °C (superheated steam). Work out the ideal cycle's efficiency by hand from steam-table values at 8 MPa and 10 kPa. Model the same cycle in code and check it matches. Then add isentropic efficiencies of 85% (turbine) and 75% (pump). Sweep the boiler pressure from 2 to 15 MPa and the condenser pressure from 5 to 20 kPa. Plot efficiency and turbine exit quality. Fill a hand-vs-code table, and explain why exit quality (often kept above about 0.88) limits the boiler pressure.
3. Fill the predicted-vs-measured (or hand-vs-simulated) table.
4. Explain every gap with a cause someone can check.
5. Write the README and ask someone who knows the subject to check it.

README
ME 3: Thermodynamics — Model a steam power plant
What I expected:
How to rerun it:
Predicted vs measured:
Why they differ:
Safety: hand tools and eye protection only

What gets sent back

• No convergence study, or no hand calculation that checks it.
• Machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy without a trained supervisor.

Resources

What a verifier looks for

• The hand calculation and the code agree within 1% for the ideal cycle, shown in a table with every state.
• The sweep plots efficiency and turbine exit quality, with units and the efficiencies used stated.
• The write-up explains the trade-off and checks one point against an energy balance.
• Check the engineering and the numbers, not just that it exists: do the units, the hand calculation and the table agree?
• Build photos show hand tools only and eye protection worn: no machine tools, welding, pressure vessels, combustion, or springs and flywheels storing dangerous energy (unless a trained supervisor and a proper workshop are shown).

You'll sign in first, then come straight back here.