Türbülanslı yanma modelleri oyf denklemleri için yeni bir hibrit sonlu-hacimler/parçacık metodu ve hız modellerinin performans değerlendirilmesi

The consistent hybrid solution method has been recently developed and shown to be superior tothe best alternative approach by as much as a factor of 50 or more, making the PDF methodologya feasible design tool in practical applications (Muradoglu et al,2003). In the present study, thehybrid solution method is improved significantly by replacing the density-based finite-volume(FV) solver with a SIMPLE type pressure-based FV solver (Peric,1996) and the new solutionalgorithm is used to simulate the bluff-body stabilized turbulent non-reacting and reacting flowsstudied experimentally by Dally et al. (1999). Non-reacting and reacting bluff-body flowsimulations are performed by Jenny et al. (2001) and Muradoglu et al. (2003), respectively. Thevelocity-turbulent frequency-compositions joint PDF model provides a complete closure forturbulent reacting flows. Mass-weighted joint PDF is defined as the probability density functionof the simultaneous events of velocity, turbulent frequency and compositions at one time and onepoint. In the PDF methods, the transport equation for mass-weighted joint PDF is directly derivedfrom the Navier-Stokes equations (Pope, 1985) and the unclosed terms are modeled throughconstruction of stochastic differential equations (SDEs). The closure is usually guided by existentReynolds stress models such that the joint PDF model is equivalent to the correspondingReynolds stress model at the second moment level. Although advanced velocity models exist, thesimplified Langevin model (SLM) has been usually used in the PDF computations due to itssimplicity. In the present study, in addition to the SLM, we also consider two other popularvelocity models, namely Lagrangian Isotropization of Production Model (LIPM) and LagrangianSpeziale Sarkar Gatski Model (LSSG) and evaluated their performances for the bluff-body flows.Due to simplicity a flamelet approach will be used in the computations. Although mean fields inreacting bluff-body flow are found less sensitive to model constants it has been found that meanfields are very sensitive in non-reacting bluff-body flow. With the modification of LIPM andLSSG a significant improvement is achieved in prediction of mean fields for non-reacting bluff-body flow.Advisor: Metin Muradoğlu Date:Director: Prof. Dr. Yaman Arkun Date: