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Show FLOW AND COMBUSTION MODELING OF VERTICAL LIME KILN CHAMBERS Essam Eldin Khalil Faculty of Engineering Cairo University Cairo, Egypt INTRODUCTION IN previuos papers, for example, references lto 7, calculated results obtained from numerical solutions of the governing conservation equations in the finite difference form have been appraised by comparisons with experimental measurements obtained in model and full scale furnaces and combustion chambers. Comparisons of calculated and measured results have shown, in general, that discrepancies in velocity, temperature, fuel concentration and wall heat flux distributions are of the order of 5%,7%,10% and 10% respectively. Such discrepancies stem partly from the uncertainities in the measurements but largely from the assumptions made in the calculation procedure and particularly from the turbulence, combustion and heat transfer models assumptions. Numerical features can also give rise to errors but these are probably of lesser significance in the relatively simple geometries of the furnaces. The present contribution extends the work of references 1,2,4,5,6&7 to larger scale industrial furnaces where the flow,geometry and burner design are more complex. In such situations,it is to be expected that the importance of radiation assumptions and numerical details will be greater. The present work demonstrated the applicability of the numerical computational schemes to complex flow and combustion in vertical lime kiln furnace producing 80 tons/day. The flow is considered as two-dimensional axisymmetric with solid-gas interactions taken into account. 99 The following section describes the calculation procedure and its cons tiuent components. It is intended to provide a clear indication of the assumptions but details are omitted where they have been documented previously. The experimental investigation. , test rig, instrumentation ' ~rror analys1s and the measured propert - les are described in the third section. The results are presented and discussed in the fourth section and relates the experimental and calculated results in a r epresenative sample of comparisons to allow an appraisal of the method. The paper ends with a general discussion and a summary of the more important conclusions and results. CALCULATION METHOD GENERAL - The flow and combustion characteristics in a vertical lime kiln are very complex due to the interaction of the aerodynamic pattern,mixing,combustion and heat transfer. The numerical analysis and investigation of such flow is an aradous task. The furnace under consideration is schematically shown in figure 1 . The complexity of the flow and the strong interaction between the physical parameters require thorough analysis of the following phenomena: • Turnulent flow characteristics • Turbulent combustion • Multi-phase flow and reaction • Heat transfer characteristics GOVERNING EQUATIONS - These phenomena are discussed here in terms of providing the closure form of the general governing equation expressed,ref.l,as |