OCR Text |
Show environments therefore presents a formidable task. This combustion chamber of the B ERL is modular with an octagonal cross-section. This design provides a reasonable compromise between access for optical probing, flexibility to vary the near burner environment and cost of construction. The octagonal cross-section represents an acceptable approximation of cylindrical symmetry, yet provides good capabilities for optical access through planar surfaces. The cross-section of 3.5 feet represents an effective furnace to burner diameter ratio of approximately 6: 1 for a nominal 1 x 106 Btu/hr burner. This is only a moderately confined situation and has been selected as a baseline configuration since ft will avoid flame impingement and will allow detailed evaluation of a wide range of burner configurations without consideration of wall interaction effects. The furnace enclosure, shown schematically in Figure 3a, is built up from several identical spool sections (Figure 3b). Each spool section comprises a basic water-cooled framework consisting of eight pillars supporting eight wall panels. The pillars and panels are sandwiched between two flanges. The panels are each approximately 12 inches high by 16 inches wide. These interchangeable panels provide different levels of optical access and near-field thennal environment. There are several possible configurations for the removable wall panels, i.e.: • Water-cooled panels which allow for maximum heat extraction to give a cold wall configuration • • Water-cooled panels with an insulating refractory lining to minimize heat extraction and to provide for a high temperature thermal environment Wall panels constructed with Vycor, or quartz windows to provide optical access through cross sections of approximately 15 inches by 11 inches high 6 Peripheral to the combustion chamber and diagnostics equipment there is a vast array of piping, ventilation, control, metering and monitoring equipment involved in the system design and implementation. The design of the ancillary equipment is intended to fulfill objectives in the following four areas: Safety The use of flammable fuel gas in a combustion test facility of this scale presents fire and explosion risks. The system includes a flame safety system with pennissives and trips which prevent unsafe operation. In addition, clearly noted emergency shut-off valves and switches will be available for manual shutdown. Control The system is designed to allow the burner operating conditions to be established accurately and repeatably. The input and output parameters will be monitored with accuracy commensurate with the intended use of the data. Flexi bility The full range of experiments to be conducted in this facility has yet to be established. Therefore, the facility design allows as much flexibility as possible, especially with respect to the ranges of fuel and air flow rates, pressures and temperatures and the number of fuel and air streams to be provided to the burners. Operability The facility will be easy to set up and operate. The operators will have a direct indication of the parameters they are controlling. For example, overall excess air will be calculated by the data acquisition system, and output to the operator in real time in stand:trd engineering units. Many of these technical requirements are linked to specifications of the BERL's ancillary equipment, such as measurement and control instrumentation. Also key to the design of ancillary and control equipment is facilitation of use by outside researchers whose costs and time investment will be reduced by minimizing the time required for developing system familiarity. Table 1 lists system specifications. |