초록 ▼

An active effective flow-through area control system includes an upstream wall-flow perturber and a downstream wall-flow perturber situated in an inlet region of an aircraft engine. The downstream wall-flow perturber is positioned downstream from the upstream wall-flow perturber. The upstream and do

An active effective flow-through area control system includes an upstream wall-flow perturber and a downstream wall-flow perturber situated in an inlet region of an aircraft engine. The downstream wall-flow perturber is positioned downstream from the upstream wall-flow perturber. The upstream and downstream wall-flow perturbers are configured to generate and trap at least one region of separated, vortical flow in the airflow through the inlet region. A method, for actively changing an effective flow-through area of an inlet region of an aircraft engine, includes creating at least one region of separated, vortical flow in an airflow passage defined by the inlet region. The method further includes trapping the region of separated, vortical flow in the airflow passage. The region of separated, vortical flow partially obstructs a main inlet airflow.

대표청구항 ▼

An active effective flow-through area control system includes an upstream wall-flow perturber and a downstream wall-flow perturber situated in an inlet region of an aircraft engine. The downstream wall-flow perturber is positioned downstream from the upstream wall-flow perturber. The upstream and do

An active effective flow-through area control system includes an upstream wall-flow perturber and a downstream wall-flow perturber situated in an inlet region of an aircraft engine. The downstream wall-flow perturber is positioned downstream from the upstream wall-flow perturber. The upstream and downstream wall-flow perturbers are configured to generate and trap at least one region of separated, vortical flow in the airflow through the inlet region. A method, for actively changing an effective flow-through area of an inlet region of an aircraft engine, includes creating at least one region of separated, vortical flow in an airflow passage defined by the inlet region. The method further includes trapping the region of separated, vortical flow in the airflow passage. The region of separated, vortical flow partially obstructs a main inlet airflow. achment means at the mouths of the bags and in that the attachment means is spaced from the mouths of the bags so as to define a gap between the attachment means and the mouths of the bags. 2. A pre-formed bags dispenser according to claim 1 wherein the stack is folded about the transverse bend so that the second portion is superimposed on the first portion in the container. 3. A pre-formed bags dispenser according to claim 1 wherein the attachment means is formed integrally with the stack, of the material of the bags of the stack. 4. A pre-formed bags dispenser according to claim 1 wherein the attachment means comprises a bar block of the material of the bags separably attached to the mouth ends of the bags. 5. A pre-formed bags dispenser according to claim 4 wherein the bar block is a T-bar block, the cross part of the T extending between and being joined to the mouths of the bags intermediate the handles. 6. A pre-formed bags dispenser according to claim 3 wherein the attachment means comprises projections on the mouth ends of the bags. 7. A pre-formed bags dispenser according to claim 3 wherein the attachment means comprises a combination of a bar block and projections at the mouth ends of the bags. 8. A pre-formed bags dispenser according to claim 5 wherein the base end of each bag of the folded stack has separably joined thereto a tab which is located with respect to the stem part of the T-bar block. 9. A pre-formed bags dispenser according to claim 8 wherein the tabs are attached to the stem part of the T-bar block. 10. A pre-formed bags dispenser according to claim 9 wherein the tabs are attached to the stem part by means of a pin passed through holes in the tabs. 11. A pre-formed bags dispenser according to claim 8 wherein the tabs are separably joined to the base ends by lines of weakening. 12. A pre-formed bags dispenser according to claim 1 wherein the access aperture is positioned and dimensioned for he nearest bag of the stack, at the second portion of the stack, to be exposed from adjacent to the mouth of the bag to the bend. 13. A pre-formed bags dispenser according to claim 12 wherein the access aperture extends around the bend of the stack. 14. A pre-formed bags dispenser according to claim 12 wherein the access aperture is enlarged at or towards the bend. 15. A pre-formed bags dispenser according to claim 1 wherein the access aperture is positioned and dimensioned, at least for the most part, for access into the container to the bag of the stack nearest to the aperture to be restricted to three extended fingers and thumb of one hand of a grown person. 16. A pre-formed bags dispenser according to claim 1 wherein the access aperture has an edge positioned to deter a person from putting his or her hand into the container between the handles of the bags of the stack. 17. A pre-formed bags dispenser according to claim 1 wherein the access aperture has an edge at which a restraint is provided positioned to deter a person from putting his or her hand into the container between the handles of the bags of the stack. 18. A pre-formed bags dispenser according to claim 1 wherein the container is of a generally box or tray-like form having a front part in which is the access aperture. 19. A pre-formed bags dispenser according to claim 18 wherein the container is of box form and is substantially closed except for the access aperture. 20. A pre-formed bags dispenser according to claim 1 wherein the container is formed from a single integral sheet of material cut and having fold lines defined therein for the container to be folded into its finished shape. 21. A pre-formed bags dispenser according to claim 17 characterized in that the container has opposite ends and sides and opposed front and back walls in the front one of which is the access aperture, and the attachment means is held captive in the container at or adjacent to one of the opposite ends. 22. A pre-formed bags dispenser according to claim 1 wherein the attachm ent means is held captive in the container by retention means engaged therewith and anchored to the container. 23. A pre-formed bags dispenser according to claim 22 wherein the attachment means comprises a bar block of the material of the bags separably attached to the mouth ends of the bags and the container has a header part which is folded around at least a part of the bar block and secured in the folded state to hold the bar block captive in the container. 24. A pre-formed bags dispenser according to claim 22 wherein the retention means comprises an anchorage element fixed in the container, and the stack of bags has a hole in or adjacent to the attachment means in which the anchorage element is engaged. 25. A pre-formed bags dispenser according to claim 1 wherein the stack of bags is folded on a support inside the container. 26. A pre-formed bags dispenser according to claim 25 wherein the support is of a plate or generally plate-like form in which there is an opening and the stack is held captive to the support, within the container, at an end part of the support, extends from that end part along one surface of the support to the opening, passes through the opening and is folded back along an opposite surface of the support, the bend of the stack being in the opening. 27. A pre-formed bags dispenser according to claim 26 wherein the support is slidable into and out of the container, the stack being loaded onto the support outside the container so as to extend along the one of surface of the support from said one end to the opening and pass through the opening, and the stack being caused to fold back against the opposite surface of the support as the support is inserted into the container. 28. A pre-formed bags dispenser according to claim 27 wherein the container has catches which snap into engagement with notches in the support when the stack is fully inserted into the container, thereby to retain the support in the container. 29. A pre-formed bags dispenser according to claim 1 wherein the container is a bag with the access aperture in a frontal part thereof. 30. A pre-formed bags dispenser comprising a container and located therein a stack of pre-formed bags and attachment means, the container having an access aperture, the bags of the stack each having a flattened body which is formed with the opposed front and back walls lying together and has a closed base end and an opposite mouth end, and the bags being retained together in the stack by separable attachment at their mouth ends to the attachment means at lines of weakening, and the stack having a transverse bend intermediate the base and the mouth ends of the bags whereby a first portion of the stack containing the base ends is deviated from a second portion of the stack containing the mouth ends in a direction towards which external surfaces of the back walls of the bags face, and a portion of the front walls of the bags at the second portion are tensioned and presented towards the access aperture such that the bag nearest to the aperture has exposed a portion of its front wall which extends from adjacent the mouth end towards the bend for that bag to be drawn out through the aperture by manual pulling of the front wall relative to the attachment means, and the separable attachment of the bags to the attachment means allows separation of the bag so pulled from the attachment means in a progressive action which opens the mouth of the bag, wherein the bags of the stack are formed with handles at their mouth ends, in that the attachment means comprises a bar block of the material of the bags extending between and separably attached to the handles and in that the container has a header part which is folded around at least a part of the bar block and secured in the folded state to hold the bar block captive in the container. 31. A pre-formed bags dispenser according to claim 30 wherein the container is a bag with the access aperture in a frontal part thereof.