GB2599949A - Aerodynamic spoiler for jetfan bellmouth - Google Patents
Aerodynamic spoiler for jetfan bellmouth Download PDFInfo
- Publication number
- GB2599949A GB2599949A GB2016446.3A GB202016446A GB2599949A GB 2599949 A GB2599949 A GB 2599949A GB 202016446 A GB202016446 A GB 202016446A GB 2599949 A GB2599949 A GB 2599949A
- Authority
- GB
- United Kingdom
- Prior art keywords
- bellmouth
- fan
- aerodynamic spoiler
- nozzle
- fan assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000009423 ventilation Methods 0.000 claims abstract description 9
- 238000009434 installation Methods 0.000 claims description 4
- 238000000926 separation method Methods 0.000 abstract description 6
- 230000000712 assembly Effects 0.000 abstract 1
- 238000000429 assembly Methods 0.000 abstract 1
- 239000002184 metal Substances 0.000 description 4
- 238000005096 rolling process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003584 silencer Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
- E21F1/003—Ventilation of traffic tunnels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/52—Casings; Connections of working fluid for axial pumps
- F04D29/54—Fluid-guiding means, e.g. diffusers
- F04D29/541—Specially adapted for elastic fluid pumps
- F04D29/545—Ducts
- F04D29/547—Ducts having a special shape in order to influence fluid flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
- F24F1/06—Separate outdoor units, e.g. outdoor unit to be linked to a separate room comprising a compressor and a heat exchanger
- F24F1/38—Fan details of outdoor units, e.g. bell-mouth shaped inlets or fan mountings
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2250/00—Geometry
- F05D2250/50—Inlet or outlet
- F05D2250/51—Inlet
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
A ventilation fan assembly has a nozzle and a bellmouth 3, and an aerodynamic spoiler 4 extending from part of the circumference of the bellmouth in order to preventing separation of the inlet flow in fan assemblies used in ventilating tunnels and other internal spaces. The aerodynamic spoiler may be integral to the bellmouth or a separate part to the bellmouth. An aerodynamic spoiler may be present on both the inlet and discharge sides of the fan assembly.
Description
AERODYNAMIC SPOILER FOR JETFAN BELLMOUTH
FIELD OF INVENTION
[0001] The present invention relates to an aerodynamic spoiler fitted to a jetfan bellmouth.
BACKGROUND OF THE INVENTION
[0002] Bellmouths are routinely used in the ventilation industry at fan inlets. They are conventionally designed to provide a smooth path with a monotonically decreasing flow area towards fan inlets, in order to prevent flow separation, and to ensure the uniformity of inlet flow.
[0003] A previous patent application number, GB256209I, filed by the present Applicant describes an improved jetfan, by tilting the nozzle trailing edge so that it forms an angle with respect to the fan centreline, with the surface of the nozzle throughbore being non-cylindrical in shape. Another patent application filed by the present Applicant, GB2562263, has the purpose of reducing the Coanda effect downstream of tunnel jetfans, in order to improve in-tunnel thrust and to enhance energy efficiency. This can be achieved by the installation of a bellmouth that can comprise a convergent section, a constant-area section and a divergent section.
[0004] In order to ensure that the flow entering the bellmouth at the inlet side of the jetfan does not separate at the vicinity of the shortest edge of the silencer throughbore, particularly for bench thrust tests, it is necessary to wrap the bellmouth throughbore around, to form a rounded nose facing the oncoming flow. This ensures that the air flowing from the discharge side of the jetfan is correctly shepherded into the bellmouth, without separating along the bellmouth or within the nozzle. 2 -
[0005] The requirement for a wrap-around surface forming a rounded spoiler along the entire circumference of the bellmouth can cause production difficulties, particularly during the rolling of stainless steel sheet metal.
[0006] The Applicant believes that there remains scope to simplify the design of bellmouths for improving the efficiency of jetfans
STATEMENTS OF THE INVENTION
[0007] According to one aspect of the invention, there is provided a fan assembly for installation in an internal space to provide ventilation in the internal space, the fan assembly being arranged or arrangeable such that a ventilating flow will pass through the nozzle throughbore before entering the fan; the assembly comprising: a fan for generating a ventilating flow, the inflow into the fan being substantially parallel to the outflow from the fan; a nozzle has a trailing edge at the distal end from the fan. and a bellmouth is attached to the nozzle trailing edge; wherein the angle made between the nozzle trailing edge and a centreline of the fan is not perpendicular; and wherein: the bellmouth throughbore is extended along part of its circumference to form an aerodynamic spoiler.
[0008] The invention provides a solution to the technical issue of how to avoid separation at the inlet to the nozzle described in GB2562091. The solution proposed in GB2562263 is feasible and proven using Computational Fluid Dynamics (CFD). However, the previous solution involved wrapping the leading edge of the bellmouth around its entire circumference. The process of rolling stainless steel sheet metal can cause significant distortions.
[0009] The solution identified by the Applicant is to develop a solution that treats the flow separation issue where it originates, namely for the flow along the shortest edge of the nozzle throughbore. Without adequate precautions, the inlet flow along the shortest edge may lift up and separate from the nozzle throughbore, causing a significant pressure drop and additional power consumption.
[0010] Separation of the flow along the shortest edge of the nozzle throughbore can be particularly acute when a jetfan manufactured in accordance with 0B2562091 is tested on a bench, as opposed to a tunnel installation This is because the angle of flow incidence at the bellmouth is much greater on a test bench rather than in a tunnel with a background velocity flowing in the same direction as the air discharged from the jetfan.
[0011] The Applicant's CFD analysis has shown that it is possible to eliminate the flow separation at the inlet by the simple expedient of using an aerodynamic spoiler to shepherd the airflow flowing from the discharge side of the jetfan. This spoiler can either be an integral part of the inlet bellmouth, or an external attachment to the inlet bellmouth. Using a spoiler described in this invention avoids the need to wrap the bellmouth surface around itself around its entire circumference.
[0012] For reversible jetfans, the present invention should preferably be used on both the inlet and outlet bellmouths. For unidirectional jetfans, the present invention should be used on the inlet bellmouth side.
[0013] The aerodynamic spoiler is preferably arranged as a rotational projection about the bellmouth axis. Such a geometry is readily manufactured using standard spinning, rolling and machining production techniques.
BRIEF DESCRIPTION OF THE DRAWINGS 4 -
[0014] A number of preferred embodiments of the present invention will now be described by way of example only, and with reference to the accompanying drawings, in which: [0015] Fig.1 shows a vertical section through an embodiment of a ventilation apparatus with a bellmouth and aerodynamic spoiler as described in this invention installed on one side of a fan assembly; [0016] Fig 2 shows an end view of an embodiment of a ventilation apparatus with a bellmouth, and with the aerodynamic spoiler arranged at the bottom of the bellmouth; and [0017] Fig. 3 shows a 3D isometric drawing of an embodiment of a ventilation apparatus with a bellmouth and aerodynamic spoiler as described in this invention installed at the end of a nozzle
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0018] Referring to Figure 1, this shows a sectional side view of an embodiment of the present invention within the inlet side of a ventilation apparatus [0019] In this embodiment, a fan assembly comprising a fan (1) extracting flow from the ambient via a nozzle (2) and a bellmouth (3). The bellmouth is extended along part of its circumference in the vicinity of the end of the shortest nozzle edge to form a partial loop which acts as an aerodynamic spoiler (4). The extension is only a fraction of the bellmouth circumference, typically in the range of a 10 to 180 degree angle measured about the bellmouth axis.
[0020] The aerodynamic spoiler (4) is shown as a thin sheet of metal in figure 1, but it could also be produced as a separate solid piece and attached to the bellmouth.
The aerodynamic spoiler can also be produced as a separate sheet of metal and welded onto the bellmouth.
[0021] Figure 2 shows an end view of an embodiment of the invention, with an aerodynamic spoiler (4) installed on a bellmouth (3). The spoiler (4) is formed by an extension of part of the bellmouth which curves back towards the assembly in a partial loop structure to form a rounded nose. The figure serves to highlight the limited angular extent of the aerodynamic spoiler. This figure indicates a preferred angular extent of 30 degrees about the bellmouth axis for the aerodynamic spoiler, but other angular extents are also possible.
[0022] This invention permits the under-hang of the bellmouth relative to the lower edge of the nozzle to be reduced or eliminated This can be achieved by rotating the nozzle and bellmouth about the fan axis, such that the aerodynamic spoiler does not protrude into the occupied space. For reversible jetfan operation, the nozzle/bellmouth angle of rotation is preferably set by reference to the required discharge angle of the flow.
[0023] It would be possible to modify an existing fan assembly in order to fit nozzles as described in this invention to one or more sides of a fan, and hence reap the benefits of improved performance [0024] This invention is equally beneficial for the ventilation of tunnels, underground car parks and similar internal spaces.
[0025] It will be appreciated that the foregoing are merely examples of embodiments and just some examples of their use The skilled reader will readily understand that modifications can be made thereto without departing from the true scope of the inventions. 6 -
Claims (6)
- CLAIMS: 1. A fan assembly for installation in an internal space to provide ventilation in the internal space, the fan assembly being arranged or arrangeable such that a ventilating flow will pass through the nozzle throughbore before entering the fan; the assembly comprising: a fan for generating a ventilating flow, the inflow into the fan being substantially parallel to the outflow from the fan; a nozzle has a trailing edge at the distal end from the fan and a bellmouth is attached to the nozzle trailing edge; wherein the angle made between the nozzle trailing edge and a centreline of the fan is not perpendicular; and wherein: the bellmouth throughbore is extended along part of its circumference to form an aerodynamic spoiler.
- 2. A fan assembly according to claim 1, wherein the aerodynamic spoiler extends the bellmouth throughbore in a partial loop to form a rounded nose.
- 3. A fan assembly according to claim 1 or claim 2, wherein the aerodynamic spoiler is integral to the bellmouth.
- 4. A fan assembly according to claim 1 or claim 2, wherein the aerodynamic spoiler is a separate part from the bellmouth.
- 5. A fan assembly according to any of the preceding claims, wherein the aerodynamic spoiler is arranged as a rotational projection about the bell mouth axis.
- 6. A fan assembly according to any of the preceding claims, wherein the aerodynamic spoiler is installed on both the inlet and discharge sides of a fan assembly.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2016446.3A GB2599949B (en) | 2020-10-16 | 2020-10-16 | Aerodynamic spoiler for jetfan bellmouth |
PCT/EP2021/078826 WO2022079316A1 (en) | 2020-10-16 | 2021-10-18 | Aerodynamic spolier for jetfan bellmouth |
EP21802205.1A EP4229277A1 (en) | 2020-10-16 | 2021-10-18 | Aerodynamic spolier for jetfan bellmouth |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2016446.3A GB2599949B (en) | 2020-10-16 | 2020-10-16 | Aerodynamic spoiler for jetfan bellmouth |
Publications (3)
Publication Number | Publication Date |
---|---|
GB202016446D0 GB202016446D0 (en) | 2020-12-02 |
GB2599949A true GB2599949A (en) | 2022-04-20 |
GB2599949B GB2599949B (en) | 2023-04-26 |
Family
ID=73598338
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2016446.3A Active GB2599949B (en) | 2020-10-16 | 2020-10-16 | Aerodynamic spoiler for jetfan bellmouth |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4229277A1 (en) |
GB (1) | GB2599949B (en) |
WO (1) | WO2022079316A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1068537A (en) * | 1996-08-27 | 1998-03-10 | Daikin Ind Ltd | Outdoor machine unit for air-conditioner |
US20060045777A1 (en) * | 2004-09-01 | 2006-03-02 | Delta Electronics, Inc. | Fans and electronic devices utilizing the same |
GB2557130A (en) * | 2015-11-02 | 2018-06-13 | Mitsubishi Electric Corp | Air conditioner outdoor unit and refrigeration cycle device |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6910327B2 (en) * | 2003-07-28 | 2005-06-28 | The Boeing Company | Apparatus and methods for varying inlet lip geometry of a jet engine inlet |
US8821123B2 (en) * | 2010-03-08 | 2014-09-02 | The Penn State Research Foundation | Double-ducted fan |
CN103307044B (en) * | 2013-07-08 | 2016-03-30 | 江苏华群科技发展有限公司 | Vector jet blower |
GB2562091A (en) | 2017-05-04 | 2018-11-07 | Mosen Ltd | Optimised tunnel ventilation device |
GB2562263A (en) | 2017-05-10 | 2018-11-14 | Mosen Ltd | Bellmouth for jetfan |
-
2020
- 2020-10-16 GB GB2016446.3A patent/GB2599949B/en active Active
-
2021
- 2021-10-18 EP EP21802205.1A patent/EP4229277A1/en active Pending
- 2021-10-18 WO PCT/EP2021/078826 patent/WO2022079316A1/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1068537A (en) * | 1996-08-27 | 1998-03-10 | Daikin Ind Ltd | Outdoor machine unit for air-conditioner |
US20060045777A1 (en) * | 2004-09-01 | 2006-03-02 | Delta Electronics, Inc. | Fans and electronic devices utilizing the same |
GB2557130A (en) * | 2015-11-02 | 2018-06-13 | Mitsubishi Electric Corp | Air conditioner outdoor unit and refrigeration cycle device |
Also Published As
Publication number | Publication date |
---|---|
EP4229277A1 (en) | 2023-08-23 |
GB2599949B (en) | 2023-04-26 |
GB202016446D0 (en) | 2020-12-02 |
WO2022079316A1 (en) | 2022-04-21 |
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