| 摘要 |
A gas turbine engine 17 having a variable-speed motor-driven fuel pump 13 is operatively arranged to supply a source of fuel to the engine through at least one combustor nozzle 19 when the engine is operating normally, is started by: providing a calibration orifice 16 sized to simulate the pressure-flow characteristics of the nozzle 19; initially directing the flow from the pump 13 through the orifice 16; operating the pump at preselected speeds; measuring the temperature of the flow and the pressure drop of the flow across the orifice at each of the preselected speeds; calculating the fuel mass flow rate as a function of pump speed and temperature; thereafter redirecting the flow from the orifice to the combustor nozzle 19 with selector valve 15; and subsequently controlling the speed of the pump 13 to produce a desired fuel mass flow rate for starting the engine. Thus a simple fuel delivery system is provided which can accommodate large changes in ambient temperature.
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