A multi-objective optimization model to enhance the comprehensive performance of underground gas drainage system

In this paper, a multi-objective optimization model, which fully considers the above factors, is built to achieve the match between the drainage system and drainage objects. Furthermore, the gas flow and methane transport model is established to calculate the values of multi-objectives and constraints. A derivative-free algorithm, bound optimization by quadratic approximation (BOBYQA), is proposed to solve the optimization model. Finally, the optimization model is applied to a typical modern coal mine and verified through the comparisons with field monitoring data and a recognized empirical formula. The optimization results reveal that (1) the variation trends of the three objectives with decision variables are different from each other, which indicates the optimal decision variables should be determined by considering all three objectives; (2) the optimization model can appropriately allocate the negative pressure in view of the interrelationship and different characteristics of drainage objects; (3) the decision variables can be adjusted to fit the characteristics change of drainage objects with time.