An approach for determining thermal performance of the unconventional lobe P–V cycles

Abstract

The purpose of this research is to present a theoretical and numerical approach to analyse the unconventional lobe P–V profiles for a heat engine cycle. The unconventional lobe P–V cycle considered here is defined as a cycle consisting of a pressure and volume relation in terms of an angle expression by continuously varying its shape to form the rounded or curved projections of the elliptical cycle. The study is deduced from a principle analysis of thermodynamic first law by using an ideal gas model. The procedure is discussed in detail in this paper, giving particular attention to the consistent evaluation of Qin and thermal efficiency by determining the adiabatic points first. Multiple adiabatic points have been found for the different lobe configurations. Effects on thermal performances due to different shapes of the lobe cycles are then examined. Finally, investigation into the number of adiabatic points and the critical values to separate different heat transfer regions is also described.