[en] Proposed is a simple model of liquid boiling process at the volume heating (without the heating surface). The model is based on the experimentally discovered fact of the appearence of spacely detached boiling layer in the upper part of the volume-heated liquid, which intensifies sufficiently the liquid circulation under the layer. This intensification is taken into account in model equations in the form of multiplier at the member, describing the cylindrical rotar circulation under the effect of thermal convection. Equation solutions of the model, obtained at the computer, agree satisfactorily with the experimental results