“…Since then, the field has progressed substantially and several types of algorithms have been developed, such as gradient-based methods, one-shot methods, gradient-free (stochastic) methods, hybrid methods, and surrogate-based methods [49,[53][54][55][56]. Considering the large number of recent publications, CFD-optimization is a rapidly developing research topic in the field of energy [57][58][59][60][61][62]. However, there exist only few previous studies in which CFD-optimization has been utilized in connection to large-scale combustion applications, such as boilers and furnaces.…”