Investigation on the effect of reformer gas on availability terms and waste heat recovery from exhaust gases of an HCCI engine considering radiation heat transfer

Abstract

The main purpose of the current study is to investigate the different effects of reformer gas on different availability terms and the capacity of waste heat recovery from a homogeneous charge compression ignition engine. A validated multizone model is utilized for HCCI engine simulation. Mass transfer and conductive heat transfer are considered between zones, and convection and radiation are considered between near-wall zone and combustion chamber walls. Four different percentages of reformer gas (0–30%) are added to main fuel, and its effects on the different availability terms are discussed. Thermomechanical availability, chemical availability, availability of work, availability loss due to convection heat transfer, availability loss due to radiation heat transfer and irreversibility are calculated. Thermal, dilution and chemical effects of reformer gas are computed separately. The results indicated that by reformer gas addition to main fuel, inlet chemical availability and availability of work reduce. Heat loss availability reduces by reformer gas addition. Irreversibility decreases by reformer gas addition and second law efficiency increases slightly. The total utilization efficiency of HCCI engines increases by reformer gas addition. The results showed that the dilution effect of RG on availability terms is more significant than its chemical and thermal effects. The dilution effect reduces both engine-produced work and second law efficiency.