Hot Gas Laboratory twin nozzle calibration

The quality of a twin nozzle flow is investigated. The assembly was manufactured to produce high temperature jet related data relevant to VSTOL aircraft when adapted to a wind tunnel hot gas facility. The twin nozzles are of an Ni-resistant flake cast iron construction whereas the standard 120 mm diameter single nozzle is a stainless steel, water-cooled fabrication. A calibration rake was used to acquire pressure and temperature data over an array of data points. The tests show that the construction method is satisfactory. The total pressure quality in the exit plane is good. A negative temperature gradient is found along the y axis. The nozzle reference pressure is a good indication of the average total pressure in the exit plane.