Clinical observations on the treatment of solitary rectal ulcer syndrome (SRUS) with stapled transanal rectal resection (STARR) surgery

Abstract

In the present study, a 3D model of the industrial thermal reactor furnace of sulfur recovery units (SRUs) was simulated using the commercial CFD code ANSYS-FLUENT. The RNG-k-ε turbulence model and the eddy-dissipation-concept for taking into account the interactions of chemical reactions and turbulent flow were used in the computational model. The radiative transport was analyzed using the discrete ordinates method. Detailed reaction mechanisms were introduced in the CFD model for providing accurate predictions of combustion and the resulting species concentrations. The furnace geometry that was identical to those used in the industry was simulated. The predicted species composition distribution, temperature distribution, and absolute pressure, were in close good agreement with the corresponding measured data. Relative errors between the CFD results and the industrial data in terms of H2S conversion and overall efficiency were, respectively, 0.081% and 0.56%. New aspects of influence of geometric parameters such as burner, choke ring, and checker wall on the hydrodynamics and thermal behavior of the reactor furnace were also discussed.