Engineering reference for Indian students

Thermal & fluids

Applied Thermodynamics

5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.

Topics

Air Standard Cycles
Air-standard efficiency of the Otto cycle is η = 1 − 1/r^(γ−1); the Diesel cycle adds the cut-off factor and the dual cycle both. Higher compression ratio r raises efficiency, bounded by knock, per P.K. Nag.
$\gamma = 1.4 for air; higher r → higher Otto efficiency$
Vapour Power Cycles
$\eta = \frac{W_{net}}{Q_{in}} = (h_{3} - h_{4} - (h_{2} - h_{1})) /$ (h₃ − h₂)
Internal Combustion Engines
Engine performance is measured by brake power BP = 2πNT/60, brake thermal efficiency η = BP/(ṁ_f·CV), and specific fuel consumption SFC = ṁ_f/BP. Mechanical efficiency links brake and indicated power, per P.K. Nag.
$Volumetric efficiency \eta_{v} = \frac{m_{actual}}{m_{theoretical}}$
Gas Turbine Cycles
The Brayton cycle efficiency is η = 1 − 1/r_p^((γ−1)/γ), depending on the pressure ratio r_p. Net work is turbine minus compressor work; the high back-work ratio distinguishes gas turbines, per P.K. Nag.
Compressors and Nozzles
Polytropic compressor work is w = n/(n−1)·RT₁[(P₂/P₁)^((n−1)/n) − 1]; multistage compression with intercooling minimises it. In a nozzle flow chokes at the throat when Mach number M = 1, with a = √(γRT), per P.K. Nag.
$Stagnation properties: h_{0} = h + \frac{V^{2}}{2}$