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Show available to validate combustion models. To create a validation document for industrial natural gas burners, Gas Research Institute (GRI) has funded a joint effort between Babcock and Wilcox and the Burner Engineering Research Laboratory (BERL) at Sandia National Laboratories in Livermore, CA. The goal of the program is to provide the measurements and documentation required to produce a complete validation document for use in the natural gas industry. The document will be constructed to provide a consistent set of operational and boundary condition information. This will allow predictions to be compared from various sources without contradictions or confusion resulting from incompatible assumptions for boundary or initial conditions. This paper describes the background for the selected test case, the measurements collected at the BERL facility, and the use of numerical modeling to guide and evaluate the validation data. THE BERL MEASUREMENTS Background and Test Facility At the start of the program, a review of measurements for industrial natural gas burner flames was conducted to identify existing data that could be used. Little data was found in the available literature that included flow and combustion measurements, although the work completed under the GRI funded SCALING 400 program (Weber, et al, 1993) provided the best set of measurements for industrial scale gas burners under controlled conditions. In particular, the 300kW measurements completed in the Burner Engineering Research Laboratory (BERL) at Sandia National Laboratories (Sayre, et aI, 1994), provided in-flame data in a well-instrumented experimental furnace. This set of measurements were selected as the baseline set. The initial burner tests, completed by the IFRF/SandialEER team, collected in-flame data for both a hotwall and cold-wall furnace configuration. Measurements were collected at six radial traverses - 27, 109, 177, 191 , 343, and 432mm downstream of the burner quarl exit. Axial and tangential velocity components, gas temperature and major species were measured at five traverses each. The data collected by Sayre et al (1994) were of excellent quality and included very good radial resolution across the flame sheet at each traverse. However, since only five traverses were completed for all of the variables, additional measurements were planned to expand the data set, resolving the flame internal and external recirculation zones and the post-flame region. Based on the existing data, the cold-wall furnace case was selected for further measurements, since this configuration offered some advantages for flame visualization, and also provided a well-defined furnace wall condition. Data from both sets of measurements will be included in the final validation document. As with the original measurements, the follow-on measurements were collected in the BERL facility. The SandialBERL furnace (Forniciari et aI, 1994) and associated equipment were designed by the Energy and Environmental Research Corp. and the University of California at Irvine Combustion Laboratory for the Gas Research Institute and the U.S. Department of Energy. The furnace is vertical, with an octagonal cross section, 1.08 m across and 2.00 m tall and is assembled from five or six identical 333 mm high spool segments. A crosssectional schematic of the furnace is shown in Figure 1. The burner is mounted in the floor and the area surrounding it is insulated with refractory board. The furnace is topped by a 390 mm tall, refractory-lined 45° cone connecting the octagonal furnace to a 305 mm I.D. exhaust duct. The first 690 mm of the exhaust duct are refractory lined. A water-cooled sampling probe used to monitor the composition of furnace exit gas is located 340 mm from the exit of the cone. The pressure in the furnace was adjusted to 12.5 Pa above ambient using a damper in the exhaust, upstream from the induced draft fan. The 300 kW swirl-stabilized natural gas burner, shown schematically in Figure 2, was built by the International Flame Research Foundation (IFRF) for the Gas Research Institute's SCALING 400 research program. The burner is circumferentially symmetric with a bluff center body containing 24 radial natural gas injection holes. Combustion air is supplied by a blower and introduced through the annular air zone and swirled using IFRF swirl blocks. The burner has the capability for flue gas recirculation (FGR) and fuel staging, but was operated only in the 3 |
