Shahriar Ghahremanian

Evaluation of RANS Models in Predicting Low Reynolds, Free, Turbulent Round Jet

In order to study the flow behavior of multiple jets, numerical prediction of the three-dimensional domain of round jets from the nozzle edge up to the turbulent region is essential. The previous n ...

A Newly Designed Supply Diffuser for Industrial Premises

Abstract The results of this investigation revealed the airflow distribution from a new design of supply diffuser under non–isothermal conditions. To illustrate the indoor climate parameters in the occupied zone, for both the heating and cooling seasons, an experimental investigation was carried out in industrial premises. The indoor climate was explored at ankle, waist and neck levels for a standing person at different positions, to determine the variation of the thermal comfort indexes and draught rating (DR) with position in the facility. The observed PPD and DR values indicate acceptable levels of thermal comfort in the facility for both summer and winter cases. The conclusion can be drawn that well–distributed airflow saves energy by removing the need for an additional heating and cooling systems during cold and hot weather seasons.

Numerical and experimental verification of initial, transitional and turbulent regions of free turbulent round jet

Three-dimensional simulation of the whole domain (initial, transition and fully developed regions) of round jet is essential in order to predict and to study the flow behavior of multiple jets (e.g. confluent jets). According to authors knowledge, numerical prediction of round jet with RANS models that has been presented by other researchers, are only in twodimensional (axisymmetric) and mostly for the fully developed region. The inlet boundary conditions, inlet velocity profile, turbulent kinetic energy and its dissipation rate at the diffuser exit has been governed from an earlier verified numerical simulation. In the present paper, results of three-dimensional modeling of isothermal, free, turbulent round jet with two two-equation (Low Re and SST ), a transition three-equation ( ) and a transition four-equation (SST) eddy-viscosity turbulence models with resolved inlet profiles are compared and validated with hot-wire anemometry. This study shows that numerical simulation of round jet with SST gives good agreement with measured mean longitudinal velocities, while transition models could only predict the initial region of round jet.

Investigation in the near-field of a row of interacting jets

Multiple interacting jets (confluent jets) are employed in many engineering applications, and the significant design factors must be investigated. Computational fluid dynamics (CFD) is used to nume ...