Energy Conversion Ideal vs Real Operation Technical Background
The simple and basic power cycles (Brayton Cycle, Otto Cycle and Diesel Cycle), power cycle components/processes (compression, combustion and expansion) and compressible flow components (nozzle, diffuser and thrust) are presented in this technical background material. In the presented power cycles, power cycle components/process and compressible flow components analysis, air is used as the working fluid.
For each power cycle, the thermal efficiency derivation is presented with a simple mathematical approach. Also, for each power cycle, a T - s diagram and cycle major performance trends (thermal efficiency, specific power output and power output) are plotted in a few figures as a function of compression ratio, turbine inlet temperature and/or final combustion temperature, working fluid mass flow rate and both isentropic compression and expansion efficiency. It should be noted that this course material does not deal with costs (capital, operational or maintenance).
For compression and expansion, the technical performance of mentioned power cycle components/processes for ideal and real operation is presented with a given relationship between pressure and temperature and compression and expansion efficiency.
Complete combustion at constant pressure with and without heat loss is presented. Six different fuels (carbon, hydrogen, sulfur, coal, oil and gas) react with air as the oxidant at different stoichiometry values (stoichiometry => 1) and oxidant inlet temperature values.
Reactants and combustion products enthalpy values change with an increase in the temperature and such enthalpy values are presented in a plot where one can notice fuel higher heating value (HHV) and flame temperature definitions. Physical properties of basic combustion reactants and products are presented in an enthalpy vs temperature plot.
The combustion technical performance at stoichiometry => 1 conditions is presented knowing the enthalpy values for combustion reactants and products, given as a function of temperature. Combustion products composition on both weight and mole basis is given in tabular form and plotted in a few figures. Also, flame temperature, oxidant to fuel ratio and fuel higher heating value (HHV) are presented in tabular form and plotted in a few figures. The provided output data and plots allow one to determine the major combustion performance laws and trends.
The technical performance of compressible flow components (subsonic nozzle, diffuser and thrust) is presented with a given relationship between temperature and pressure as a function of the Mach Number and isentropic nozzle and diffuser efficiency.
The compressible flow components T - s diagrams and their major performance trends (stagnation over static temperature and pressure ratio values) are plotted in a few figures as a function of the Mach Number.
In this technical background material, one gets familiar with the simple and basic power cycles and power cycle components/processes, compressible flow components and their T - s and h - T diagrams, ideal vs real operation and major performance trends.
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