5 Gas turbine cycles Text

Pagina 1

COURSE OF ENERGY CONVERSION A 2014/2015 Prof. G. Valenti 5th Project Gas Turbine Cycles The present project aims at calculating, with the aid of the software Turbogas, the predicted performance of different gas turbine cycles varying the most significant operating parameters. Consider: - A) simple cycle gas turbine - B) intercooled gas turbine (IC) - C) regenerative gas turbine - D) intercooled – regenerative gas turbine (ICR) Assume the characteristics values provided in the next page. For data not explicitly reported, adopt the software default. It is required to: i) plot the performance of the four cycles in the efficiency – specific work chart, varying the pressure ratio  within a range of  = 4 and  = 40 ( = 90 for case B), at a TIT (total temperature at the turbine first rotor inlet) equal to 1200°C. As far as the intercooled gas turbine cycles are concerned, consider a pressure ratio of the first compressor equal to BP = totale 1/3 and BP = totale 1/2 for cases B and D, respectively. ii) report in a table or a bar chart, the entropy analysi s of the four cycles at the  which maximises the efficiency, highlighting the following irreversibilities terms:  combustion;  compression;  expansion;  exhaust venting;  regeneration;  filter/silencer pressure losses;  intercooling;  various (mechanical and electrical losses) ; Compare and comment on the obtained results. iii) at the value of  which maximises the cycle efficiency, obtained at point i), represent the curve of  in simple cycle, within a TIT range between 900°C and 1300°C, at the following values of maximum blade wall temperature: - Tmax blade= Tmax blade, base + 100C - Tmax blade= Tmax blade, base + 300C - adiabatic turbine (near infinite value of Tmax blade, i.e. Tmax balde = 5000C) iv)…