| 摘要 |
A flow control valve for a combustion unit includes a first member (48) located in a fuel or air flow path so as to define an annular flow therearound. A second member (68) is mounted so as to be rotatable substantially around the first member and a flow path is defined between the first and second members. Rotation of the second member (68) about the first member (48) causes a cyclical variation of the effective cross sectional area of the flow path, with a single cycle of relative rotation of the first and second members causing the effective cross sectional area of the flow path to pass through a plurality of maxima and minima. Fuel leaving the valve thus has a steady component defined by the minimum fuel flow and an unsteady component defined by the variable fuel flow. The unsteady component may be brought into antiphase with a detected noise or vibration level, in order to minimise such noise or vibration. |
