Two-fluid flows arise in various engineering applications. The modeling of mixtures of heterogeneous fluids is carried out within the framework of homogeneous or heterogeneous models. For homogeneous models, it is assumed that the components of the mixture do not have explicit boundaries and proper volumes, and the pressure in the mixture is calculated as the sum of the partial pressures of the components. For more complex heterogeneous models it is assumed that each component of the mixture occupies its own volume. In this case, the pressure in the mixture is calculated using the equations of state of the components and their volume fractions in the mixture. As the experience of numerical modeling shows, The field of applicability of the heterogeneous model is wider than the homogeneous one. In particular, heterogeneous model allows to simulate not only gas mixtures, but also gas-liquid mixtures. In this paper, a quasi-gasdynamic regularization is presented for a heterogeneous model of a flow of a mixture of compressible fluids. Based on the formulations [1], the homogeneous model [2] was modified and a so-called simplified model consisting of four equations with equations of state of a stiffened gas was obtained. Such a model with excluded volume concentrations and a quadratic equation for the total pressure of the components can be called a quasi-homogeneous form. In contrast to [1], the numerical algorithm uses central difference approximations of all spatial derivatives. The solving of a number of test problems shows that the presented algorithm is a reliable way to simulate the flows of heterogeneous mixtures. The algorithm is constructed in a form convenient for subsequent implementation into the OpenFOAM open software package, as an addition to the homogeneous gas mixture model based on regularized gas dynamic equations already included in this complex.