Effects of Initial Temperature, Initial Pressure, and External Heat Flux on the Thermal Behavior of Ethanol/Biodiesel as Biomass Structures

Abstract

The emergence of significant environmental problems, the depletion of fossil fuel reserves, and the anticipation of price hikes have driven researchers to explore and adopt renewable fuels derived from biological sources. Such renewable energy sources include biomass, biodiesel (BD), ethanol, bioethanol (BE), among others. Biomass is a form of energy that can be obtained from waste or the cultivation of specific plants. Notably, BD fuel can be produced from organic sources, such as animal fats or waste oil from restaurants, which is a considerable advantage of BD. Moreover, BE is a non-toxic, safe, and biodegradable fuel, and ethanol produced biologically is referred to as BE, which represents a renewable fuel with a non-fossil origin. Against this backdrop, the upcoming research employs two types of alcoholic fuel, ethanol and BD, as biomass structures. Using molecular dynamics (MD) simulation, the study evaluated the effects of temperature (Temp), pressure (Press), and external heat flux (EHF) on thermal parameters, such as HF and thermal conductivity (TC). The evaluation results indicated that an increase in the initial temperature from 1800 to 2000 K led to higher mobility of the samples, resulting in an increase in the values of HF and TC from 488 to 551 W/m2 and 0.26–0.32 W/m.K, respectively. Similarly, raising the initial Press from 1 to 5 bar increased the number of oscillations and mobility of the structures, leading to increased HF and TC values from 488 to 551 W/m2 and 0.26–0.32 W/m.K, respectively. Notably, the EHF changes exhibited similar behavior. Additionally, a significant outcome was observed when the EHF rose from 1 to 5 W/m2. This increase in EHF led to a corresponding rise in the number of reactions occurring in the studied structure. As a result, the released heat intensified, leading to increased HF and TC values. Specifically, HF values rose from 503 to 538 W/m2, and TC increases from 0.28 to 0.31 W/m.K.