THM-24

Diesel efficiency

Ideal diesel cut-off.

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GoverningDiesel efficiency

Governing equation

\eta=1-r^{1-\gamma}(\rho^\gamma-1)/(\gamma(\rho-1))

where

r: r (—)
rho: rho (—)
g: g (—)
eta: Diesel efficiency (—)

Lecture brief

Historical brief

Carnot (1824), Clausius entropy, the first law and later van der Waals and Gibbs potentials turned heat into a state science. The sheets compute work, efficiency and vapour pressure. This sheet (THM-24 — Diesel efficiency) is the form associated with Diesel efficiency. Working symbols: $r$ , $rho$ , $g$ $\rightarrow$ $eta$ . Ideal diesel cut-off. Pedagogical SI sheet with a live model and a swept parameter.

Purpose

Purpose: compute

eta

from

r

rho

g

in Thermodynamics via

\eta=1-r^{1-\gamma}(\rho^\gamma-1)/(\gamma(\rho-1))

Ideal diesel cut-off. Use it when a real thermodynamics question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

r = 18.000\,\mathrm{—}

rho = 2.000\,\mathrm{—}

g = 1.400\,\mathrm{—}

, the governing relation

\eta=1-r^{1-\gamma}(\rho^\gamma-1)/(\gamma(\rho-1))

yields

eta = 0.632\,\mathrm{—}

. One governing identity, SI units, a single sweep on the sheet. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

r r18 —rho rho2 —g g1.4 —

Outputs

Diesel efficiency eta0.632 —

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Narration of this film

One governing identity, SI units, a single sweep on the sheet.

Ideal diesel cut-off. Pedagogical SI sheet with a live model and a swept parameter.

Reading speed

Watch on YouTube