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Show RECENT DEVELOPMENTS IN PHYSICAL FLOW MODELING OF UTILITY SCALE FURNACES D. K. Anderson, J. D. Bianca Combustion Engineering, Inc. Windsor, Connecticut, USA ABSTRACT This paper summarizes recent physical flow modelmg carried out at Combustion Engineering's Krelslnger Development Laboratory. Included Is a review of current Instrumentation, experimental facil1ties, and techniques for the isothermal modeling of full scale industrial furnaces. Equipment used for flow visualization, three dtmenstonal veloctty mapptng, and the stmulatton of fuel/air mixing are discussed .. A description of a new tangential-fired furnace flow model is also given. This large-scale furnace model is surrounded by an instrument traversing system which allows the placement of various instrument packages around and within the model envelope. The instruments that have been used in this fac111ty Include a multi-hole p1tot tube, a laser absorption spectrophotometer, and a two-axts laser doppler anemometer. Experimental information from this model has been used to predict such 1mportant furnace parameters as slagglng potential, fuel-air mtxtng, and fuel burnout. Otfler recent physical modellng experiments are discussed and include the development of a high turndown coal burner assembly, and overall furnace modeling studies for a recovery and a wood-fired boiler. INTRODUCTION/BACKGROUND PHYSICAL MODELING OF COMBUSTION SYSTEMSAs summarized by Beer and Chigier ( 1 t the use of 1sothermal physical models of a practical combustion system represents a valuable engineering too I f or the designers of such systems. Salvi and Payne (2) point out that, based on the use of partial modeltng of the combustion processes, frequent use 1s made of isothermal models to predict the flame aerodynam1cs of Industrial sized burner/combustor systems. In a recent review of the fluid dynam1cs of coal combustion, BeerL Chomiak, and Smoot (3), note that whatever is Know about the aerodynamics of pulverized-coal furnaces is based on 1sothermal 117 J. G. McGowan University of Massachusetts Amherst, Massachusetts, USA model studies. They state that the flow in the combust ion chamber of pulverized-coal boi lers is the most difficult and least know problem of combustion aerodynamics. Spectfically, this problem 1s compl1cated by the large size of such systems, the use of a multitude of mteracting and often sw1rltng burner jets, and the potential variat Ion in firing systems (horizontal, tangential, Qr downshot). At Combustion Engineering, recent conventional applications of Isothermal physical model1ng have Included the flow model1ng of entrainea type gasifiers (4), utility sized tangential furnaces (5), and the development of pulverized coal burners for high turndown (6). In add1tion Isothermal modeHng nas been used as a design tool for air pollution, gas handl1ng, and large furnace heat eXChanger systems. For example, Engelbrecht (7) used Isothermal flow models to study the gas flow distribution, gas temperature distribution, and dust loadlng distribution tn electrostatic prectpttators. Thompson, et. al. (8) used physical flow model1ng techniques to evaluate upper furnace mtxlng tn overflre air and burner zone combust Ion products. Also, Anderson, Bianca, and McGowan (9) used the results of a cold flow model1ng study as an input to a digital computer program to predict the effects of gas side flow disfrlbutlon on a process heat eXChanger for a coal l1quefactlon system. . As the last example pOints out, use of physical flow model1ng as an input to a complex heat exchanger design program represents another valuabre use for this experimental technique. The same use can be made of such information for detailed combustion process simulation programs. For example, a summary of current mathematical models for large boiler combustion chamber Simulation (10) pOints out that many of these models require the direct input of fluid flow patterns from such tests. RECENT DEVELOPMENTS IN EXPERIMENTAL FLOW MODELING TECHNIQUES- A number of recent developments in the fields of flow visualization, flow measurement. and gas concentratton |