Abstract: A helical fractal heat exchanger comprises a heat exchanger core defining a plurality of helical, first fluid conduits arranged in a two-dimensional grid configuration, and plurality of helical, second fluid conduits in thermal communication with the first fluid conduits. A first fluid inlet structure splits a first fluid from a first fluid inlet of the heat exchanger and supplies it to each of the plurality of first fluid conduits, and a first fluid outlet structure recombines the first fluid from the plurality of first fluid conduits and conveys it to a first fluid outlet of the heat exchanger. The first fluid inlet and outlet structures are each fractal structures comprising at least two multi-furcation stages in which a parent channel divides into two or more sub-channels that diverge away from each other.

Abstract: A servo valve includes first and second nozzles spaced apart from each other, an elongate control member positioned between the nozzles, and a solenoid assembly surrounding at least a portion of the control member. The elongate control member has a first end and an opposing second end. The control member is configured to translate in response to the solenoid assembly being energised, such that the first end is moved towards the first nozzle and the second end is moved away from the second nozzle or the first end is moved away from the first nozzle and the second end is moved towards the second nozzle.