Gasoline surrogates in nucleate boiling heat transfer

Abstract

Many correlations to estimate the heat transfer coefficient (HTC) in nucleate boiling with binary, ternary or multicomponent mixtures are available in the literature. These correlations are usually based on phase-equilibrium parameters. Direct calculation of the HTC in mixtures with hundreds of components, such as gasoline, is thus practically impossible, as the phaseequilibrium data for such mixtures cannot be easily obtained or calculated. In research fields such as droplet evaporation and mixture thermodynamics, surrogates are constantly used to replace these multicomponent mixtures in calculations; however, this method has not yet been used in boiling research. Here, gasoline surrogates are proposed to estimate the HTC during nucleate boiling. A Monte Carlo search for the optimal composition is used to find the surrogates, and their applicability to gasoline-ethanol blends is evaluated. Two of the surrogates tested matched the experimental data well: surrogate B (16.4% n-butane + 83.6% isooctane) and surrogate C (26.2% n-butane + 42.1% n-hexane + 31.7% isooctane). Both surrogates allowed the HTC for gasoline (3.6% and 3.5% overall average deviation, respectively) and gasoline-ethanol blends (5.6% and 6.9% deviation at 400 kW/m 2 heat flux, respectively) to be estimated accurately.

Discrete model to estimate nucleate boiling heat transfer coefficient with gasoline using a double-log-normal distribution function

“…Table 4 presents the OAD for the aforementioned surrogates obtained with each distribution function, where we see the double-log-normal distribution function provided a very accurate surrogate. We also included results with the surrogate C proposed by Oliveira et al [35], a 3-component mixture containing 26.2% n-butane, 42.1% n-hexane, 31.7% isooctane. This surrogate was found empirically using the Monte Carlo search for the composition that matched the best with the gasoline experimental data by the same authors (which are the same presented in Fig.…”

“…To the authors' knowledge, the use of surrogates in nucleate boiling heat transfer was not existent before our previous work [35], where Monte Carlo search was used to find a mixture that could represent gasoline in nucleate boiling correlations. Nevertheless, that method was highly empirical because it depended on experimental data to determine the surrogate composition.…”

Método discreto aplicado à ebulição nucleada com gasolina

“…Tal abordagem pode ser observada em estudos de evaporação de gotas, termodinâmica de misturas, e combustão (Elwardany et al, 2013;Su e Chen, 2015;Al Qubeissi et al, 2015;Elwardany et al, 2016). No que se refere à aplicação de tal abordagem à ebulição nucleada, pode-se citar um trabalho deste grupo de pesquisa (Oliveira, Alegre, e Santos, 2019). Entretanto, a proposta de tal trabalho apresenta a contrapartida da necessidade de dados experimentais para determinar os suplentes, cuja composição é obtida a partir do método de Monte Carlo de forma a minimizar o desvio entre modelo e dados experimentais no cálculo do h. A aplicação de suplentes gerados de maneira totalmente preditiva à modelagem de ebulição nucleada em gasolina, no entanto, não foi ainda alvo de investigação aprofundada.…”