Simplex ray-object intersection algorithm as ray tracer for Monte Carlo simulations in radiative heat transfer analysis

In the thermal radiation analysis via Monte Carlo method, considerable computational resources are consumed to find the intersection point of an emitted energy bundle with radiant enclosure walls. Therefore, an efficient algorithm for ray-object intersection in complex geometries may cause saving time and computational effort. This paper presents a new ray-object intersection algorithm based on the well-known simplex method from linear programming. This algorithm works by searching a point in the feasible region which is defined by a set of plane equations of enclosure boundaries that maximize the line equation of the emitted energy bundle as the objective function. This algorithm is examined for two benchmark problems, namely two parallel plates with gray specular surfaces and a box with gray diffuse walls both in three-dimensional case. Although the computation time of the new proposed method is a bit higher than the conventional time, it is easy to implement because simplex algorithm is readily available as separate module in most programming languages. By using this algorithm number of objects which must be checked in complex geometries will be reduced considerably.