AN OPEN VERTICAL WIND TUNNEL

Abstract

Invention relates to an open vertical wind tunnels for simulating a free fall sky diving. An open vertical wind tunnel comprising: a frame structure (1), a power unit (2) and a fan assembly (3); a flow straightening assembly (4) comprising a vertical cylindrical housing (42) to be mounted above and coaxially with the propeller (3); a central cone (43) disposed within and coaxially with the vertical cylindrical housing (42); a plurality of radially oriented vertically disposed guide vanes (44), where each guide vane (44) is configured to straighten an air flow and absorb created noise; a flight platform (5); and sound attenuating panels (6) arranged around the open vertical wind tunnel.

Claims

1. An open vertical wind tunnel comprising: a frame structure, wherein at least some sections between beams of the frame structure are covered by perforated metal plates and a hollow volume in the frame structure enclosed by the perforated metal plates is filed with sound absorbing material; a power unit attached to the frame structure; a fan assembly; a flow straightening assembly comprising: a vertical cylindrical housing mounted above and coaxially with the fan assembly, wherein a part of an inner surface of the vertical cylindrical housing is inclined and perforated, and a hollow volume in the vertical cylindrical housing is filled with sound absorbing material; a central cone disposed within and coaxially with the vertical cylindrical housing, wherein a lateral surface of said central cone is perforated and a hollow volume in said central cone is filled with sound absorbing material; and a plurality of radially oriented vertically disposed guide vanes, wherein each guide vane (44) is attached to an inner surface of the vertical cylindrical housing and the central cone; and a flight platform comprising a safety net and safety cushion there around, and wherein the guide vane comprises a curved leading section and straight trailing section as integral parts of the guide vane and the guide vane from both of its sides is covered by a perforated metal sheet forming perforated shell of the guide vane, wherein a curved leading section is aerodynamically formed to be able to receive a whirling airflow generated by the fan assembly and guide said airflow to the straight trailing section straightening said airflow parallel with the central axis of the flow straightening assembly.

2. (canceled)

3. The open vertical wind tunnel according to, claim 1, wherein a hollow volume in the straight trailing section encompassed by the perforated metal sheet is filled with a sound absorbing material.

4. The open vertical wind tunnel according to claim 3, wherein a hollow volume in the curved leading section is filed with a sound absorbing material.

5. The open vertical wind tunnel according to claim 1, wherein a cross section of the guide vane, which is parallel to the straightened air flow, increases along the guide vane in a straight trailing edge section in the direction towards the central cone.

6. The open vertical wind tunnel according to claim 1, wherein the open vertical wind tunnel further comprises sound attenuating panels arranged around the open vertical wind tunnel, wherein an inwards faced surface of each sound attenuating panel is covered with perforated metal plate and an outwards faced surface of each sound attenuating panel is covered with solid metal plate.

7. The open vertical wind tunnel according to claim 6, wherein an area between perforated metal plate and solid metal plate of the sound attenuating panel is filed with sound absorbing material.

8. The open vertical wind tunnel according to claim 1, wherein the fan assembly comprises a flywheel which is configured as a load bearing structural element for connecting fan blades to a drive shaft of the power unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 illustrates an open vertical wind tunnel.

[0019] FIG. 2 illustrates a frame structure 1 with installed electrical power unit 2, a fan assembly 3 and a flow straightening assembly 4.

[0020] FIG. 3 illustrates a frame structure 1.

[0021] FIG. 4 illustrates a flow straightening assembly 4.

[0022] FIG. 5 illustrates a cross section of a flow straightening assembly 4 and a flight platform 5.

[0023] FIG. 6 illustrates a guide vane 44 in axonometric view.

[0024] FIG. 7 illustrates a guide vane 44 with indicated cross-sections.

[0025] FIG. 8 illustrates cross sections of the guide vane 44 (illustrated in FIG. 7) in the direction towards the central cone 43.

[0026] FIG. 9 illustrates another embodiment of a guide vane 44 with a non-perforated section 47 of the guide vane 44.

[0027] FIG. 10 illustrates a partly assembled fan assembly 3 with blades 33.

DETAILED DESCRIPTION OF THE INVENTION

[0028] FIG. 1 illustrates partly assembled open vertical wind tunnel comprising a flight platform 5 including safety cushion 51 (see FIG. 5) and sound attenuating panels 6 positioned around the vertical wind tunnel. Due to sound attenuating panels 6, other parts of the vertical wind tunnel are not visible for ordinary user. The vertical wind tunnel further comprises a safety guard comprising vertically arranged rods 7 and a net. The net is not shown for sake of clarity.

[0029] The open vertical wind tunnel further comprises a frame structure 1, a power unit 2 installed in said frame structure 1; a fan assembly 3 and a flow straightening assembly 4 (see FIG. 2). The frame structure 1 is composed of beams 11 (see FIGS. 2 and 3), wherein a perforated metal plates 12 including sound absorbing material are mounted to facilitate a sound reduction. The volume encompassed by the beams 11 and perforated metal plates 12 are filed by sound absorbing material (not shown in FIGS. 2 and 3). The fan assembly 3 is mounted on the driving shaft of the power unit 2. The fan assembly 3 (see FIG. 10) comprises fan blades 32, a flywheel 31, which is configured as a load bearing structural element, a fan blade attachment unit 33 for connecting fan blades 32 to the fan assembly 3.

[0030] In FIGS. 2, 4 and 5 the flow straightening assembly 4 comprises a vertical cylindrical housing 42 mounted above and coaxially with the fan assembly 3, wherein a part of an inner surface of the vertical cylindrical housing 42 is inclined and perforated. The flow straightening assembly 4 further comprises a central cone 43 disposed within and coaxially with the vertical cylindrical housing 42. A lateral surface of said central cone 43 is perforated. Moreover, the flow straightening assembly 4 further comprises a plurality of radially oriented vertically disposed guide vanes 44, wherein each guide vane 44 is attached to an inner surface of the vertical cylindrical housing 42 and the central cone 43. An inner section or a hollow volume of the cylindrical housing 42 and central cone 43 are filed with a sound absorbing material.

[0031] FIGS. 6 to 9 illustrate guide vanes 44 in detail. The guide vane 44 comprises a curved leading section 45 and straight trailing section 46. Both section 45 and 46 are integral parts of the guide vane 44. The guide vane 44 from both of its sides is covered by a perforated metal sheet 47 forming perforated shell of the guide vane 44. The curved leading section 45 is aerodynamically formed to be able to receive a whirling airflow generated by the fan assembly 3 and guide said airflow to the straight trailing section 46 straightening said airflow parallel with the central axis X of the flow straightening assembly 4 (see FIG. 5).

[0032] The guide vane 44 may further comprise a section not covered by perforated metal sheet or non-perforated section 47 of the guide vane 44. The non-perforated section 47 of the guide vane 44 is arranged on a side that is to be connected to the central cone 43. The non-perforated section 47 has attachment points and reduced cross section to ease installation of the guide vane 44 to the central cone 43.

[0033] While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. Therefore, it is intended that the inventions not be limited to the particular embodiments disclosed herein.