There is disclosed a flow control nozzle for controlling the flow of an incompressible fluid, the flow control nozzle having a flow area and comprising a deformable element comprising a shaped memory alloy (SMA) material wherein within a range of operating temperatures the SMA material is configured to reduce the flow area of the flow control nozzle as the operating temperature increases. The flow control nozzle is thus able to dynamically compensate for changes in operating temperature in order to maintain a constant flow.