In this talk I will discuss a natural generalization of a classical Frank-Kamenetskii model of thermal explosion in the presence of a vortical flow in two dimensional setting. This model describes possible stationary temperature distributions in a combustion vessel which boundary is maintained at a constant temperature. The model constitutes a Dirichlet boundary value problem for a certain semi-linear elliptic equation that depends on a parameter λ (Frank-Kamentskii parameter) and represents a strength of the reaction. A remarkable property of this problem is that it admits a classical minimal solution when the Frank-Kamnetskii parameter does not exceed some critical value λ∗ and no classical solutions for λ > λ∗. The absence of a classical solution, in the framework of Frank-Kamnetskii theory, is associated with the thermal explosion event. Consequently, in the context of the model λ∗, called an explosion threshold, is a maximal value of the reaction strength which allows to attain thermal equilibrium within a combustion vessel and thus provides a sharp characterization of thermal explosion. A critical temperature distribution corresponding to λ∗ is called an extremal solution. In this talk I will show that under an assumption of sufficiently fast growth of the reaction term there exists a regular vortical flow that allows to adjust an explosion threshold by reversing its direction provided that combustion vessel is not a disk. I will also discuss certain properties of the extremal solutions. In particular, it will be shown that extremal solutions are always classical. This is a joint work with Tianyi Guo.