Abstract: In a method for the thermal conditioning of electronic equipment mounted on aircraft, a flow of ram air is tapped and transferred to first means enabling said flow of air to be given a first negative gradient of temperature after which, if necessary, the flow air coming from said first cooling means is transferred to second means capable of giving a second negative gradient of temperature to said flow of air, after which the flow of air coming directly from the first cooling means, combined as the case may be with the flow of air coming from the second cooling means, is transferred to the immediate vicinity of the electronic equipment to be cooled, thus achieving an appropriate thermal conditioning of said electronic equipment. The disclosure also relates to the systems designed for the implementation of this method.

Abstract: The cross-sectional area of the airflow duct on at least one face of the fan housing is larger than the cross-sectional area of a cylindrical portion of duct which cooperates with the impeller. A junction portion having an S-shaped cross-section in an axial plane is provided on at least part of the duct periphery between the cylindrical portion and that housing face. The fan duct progressively increases in width from the cylindrical portion to the housing face and the S-shaped junction portion has a point of inflection substantially at the midpoint of its axial length. A reduction in noise level is thus achieved during operation of the fan.