Abstract
A vortex generating exhaust component is installed in-line within a marine exhaust system downstream of the water can whereby a mixture of hot exhaust gas and entrained cooling water flows there through and vortex flow is enhanced by the component to increase cooling of exhaust gas by increasing the mixing of hot exhaust gas with entrained cooling water thereby resulting in enhanced exhaust gas cooling.
Claims
1. A method for enhancing exhaust gas cooling in a marine exhaust system having exhaust pipe defining an interior volume through which exhaust and entrained cooling water flow, said method for enhancing exhaust gas cooling comprising: inducing vortex flow in the exhaust gas using at least one bluff body disposed within the interior volume of the exhaust pipe, wherein said bluff body comprises a tab; whereby vortex flow enhances interaction between the exhaust gas and entrained cooling water to increase exhaust gas cooling.
2. A method of cooling marine exhaust gas carrying entrained cooling water through exhaust pipe, said method comprising: inserting in the exhaust pipe a structure including at least one tab; said tab inducing vortex flow in the exhaust gas, thereby enhancing mixing of water and exhaust gas resulting in increased exhaust gas cooling.
Description
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
(1) FIG. 1 is a side sectional view of water jacketed marine exhaust component in accordance with the prior art;
(2) FIG. 2 is a side sectional view of an alternate embodiment water jacketed marine exhaust component in accordance with the prior art;
(3) FIG. 3 is yet another side sectional view of an alternate embodiment water jacketed marine exhaust component in accordance with the prior art;
(4) FIG. 4A is a schematic block diagram showing a vortex generating component in accordance with the present invention shown in spaced downstream relation with a water can;
(5) FIG. 4B is a schematic block diagram showing a vortex generating component in accordance with the present invention shown integrated with the downstream end of a water can;
(6) FIG. 5 illustrates a vortex generating marine exhaust component in accordance with the present invention;
(7) FIG. 6 is a sectional view thereof taken along line 6-6 in FIG. 5;
(8) FIG. 7 is an end view thereof;
(9) FIG. 8 is a partial detail of the area circled and identified as 8 in FIG. 6;
(10) FIG. 9 is an alternate embodiment water can having an outlet adapted with vortex generating structure in accordance with the present invention; and
(11) FIG. 10 is a partial detailed view illustrating vortex flow generated by the vortex generating tabs.
DETAILED DESCRIPTION OF THE INVENTION
(12) With reference to the drawings, FIGS. 4A-10 depict a vortex generating marine exhaust component, generally referenced as 10, for installation downstream from a water can of the type known in the prior art as discussed above. In a preferred embodiment, vortex generating exhaust component 10 is installed in a marine exhaust piping system downstream of the water can whereby a mixture of hot exhaust gas and entrained cooling water flows through vortex component 10. Vortex generator 10 enhances cooling of exhaust gas by creation or enhancement of whirling/turbulent exhaust gas flow that significantly enhances the mixing of hot exhaust gas with entrained cooling water thereby cooling the exhaust gas to a greater degree than would be realized in an identical system not adapted with component 10.
(13) FIGS. 4A and 4B provide schematic illustrations depicting alternate installation applications for vortex component 10. In a preferred embodiment, vortex generator 10 is installed in marine exhaust piping in downstream spaced relation with the water can as illustrated in FIG. 4A. In an alternate embodiment, however, the vortex generator may be integral with exhaust pipe at the discharge end of the water can as illustrated in FIG. 4B. Accordingly, as used herein the term “vortex generating exhaust component” or “vortex generator” and similar variations thereof shall broadly be construed to mean the inclusion of vortex generating structure either within a section of exhaust pipe or duct, or alternatively the adaptation of said structure to the outlet end of a marine water can.
(14) In the preferred embodiment depicted in FIG. 4A, a marine engine 100 discharges hot exhaust gas 101 into a water can 102. In addition, marine engine 100 discharges cooling water 103, which has circulated through the engine after having been drawn from the body of water (e.g. ocean) through a cooling water inlet 104 upon which the vessel travels. Cooling water 103 is injected into water can 102 as is known in the art as discussed above. Cooling water 103 is injected into the hot exhaust gas 101 by water can 102 and a portion thereof is flashes to steam, while the remainder thereof is entrained with the rapidly flowing exhaust gas. The exhaust gas and entrained cooling water pass through vortex component 10 whereby whirling flow is generated to induce mixing and evaporation of entrained cooling water with the exhaust gas. The flow eventually is routed to a vessel discharge location whereby the flow is discharged from the vessel. In the alternate embodiment depicted in FIG. 4B, vortex generator 10 is illustrated as being integrally associated with water can 102, namely the discharge end of the exhaust pipe being modified with the vortex generating technology as disclosed herein. FIG. 9 illustrates the embodiment schematically shown in FIG. 4B.
(15) Turning now to FIGS. 5-8, vortex generating exhaust component 10 will now be described in an embodiment wherein the component is included in a section of exhaust pipe as schematically illustrated in FIG. 4A. Vortex generating exhaust component 10 includes tubular exhaust duct 12 which is generally fabricated from temperature resistant materials, such as fiberglass, in accordance with known practices in the art. Exhaust duct 12 has an inlet 12a and an outlet 12b. Exhaust duct 12 includes a truncated conical vortex generator 14 disposed therein, which includes an inlet end and an outlet end, which are generally referenced as 16 and 18 respectively.
(16) Vortex generator 14 comprises an annular structure which is concentrically disposed within, or otherwise connected to, exhaust duct 12. In a preferred embodiment, inlet end 16 defines a diameter which is greater than the diameter of outlet end 18 so as to increase the velocity of the exhaust gas as it flows through vortex generator 14. A plurality of circumferentially disposed and angularly spaced vortex generating tabs 20 project from the outlet end 18 thereof. Tabs 20 are angularly spaced thereby defining gaps 22 therebetween. Tabs 20 project in a radially inward and downstream orientation to form bluff bodies that interact with exhaust gas flow to generate turbulent vortex flow downstream of the tabs. In a preferred embodiment, wherein exhaust duct 12 has an inlet of 14″ and an outlet of 12″, tabs 20 are sized with a length of approximately ¾″ and a width or approximately ½″ and are disposed with a gap spacing of approximately ½″. In addition, tabs 20 are angled radially inwardly between approximately 20-40 degrees. As should be apparent, however, any suitable tab configuration, sizing, and spacing is considered within the scope of the present invention. Further, the radially inward angle may be varied for different applications. In addition, it is important that the tabs are disposed such that the side edges thereof are squared with the direction of flow (e.g. not pitched about a longitudinal tab axis relative to the direction of flow) to avoid creating a spiral flow within the downstream exhaust conduit which can result in undesired centrifugal separation of entrained water from the exhaust gas. In applications wherein the terminal end 12b of exhaust duct 12 is connected to an elbow (not shown) it may be desirable to include a deflecting baffle 13, suitably angled so as to deflect the flow in the desired direction. FIG. 7 is an end view depiction further illustrating deflecting baffle 13. FIG. 8 is a partial detailed view illustrating tabs 20 and gaps 22.
(17) FIG. 6 depicts a cross-sectional illustration of vortex generating exhaust component 10 fabricated from temperature resistant fiberglass. Vortex generating exhaust component 10 includes tubular exhaust duct 12 having an inlet 12a and an outlet 12b. Exhaust duct 12 includes a truncated conical vortex generator 14 disposed therein, which includes an inlet end 16 and an outlet end 18. Tabs 20 are depicted projecting downstream and radially inward. In addition, vortex generator 14 is shown as reducing in diameter from the inlet 16 to the outlet 18. Vortex generator 14 may be integrated into exhaust duct 12 by forming the duct with a double wall structure as seen in FIG. 6. Reinforcing crush resistant rings 15 are disposed within the double wall structure to prevent installation pipe clamp rings from crushing the fiberglass outer wall upon installation.
(18) Turbulence and vortex flow is induced in exhaust gas and entrained cooling water flowing through the vortex generator 14 thereby enhancing mixing of water and gas which results in increased water to vapor phase change (i.e. vaporization/evaporation) thereby causing the absorption of heat from the hot exhaust gas in accordance with the principals of thermodynamics. It has been found that the addition of a vortex generating exhaust component in accordance with the present invention in one application, achieved a significant exhaust gas temperature decrease of 40-50 degrees Fahrenheit, as compared to measurements obtained on said system when not adapted with the vortex generating technology disclosed herein. Accordingly, the vortex generating component induces a vortex-type whirling turbulent flow in the exhaust gas and entrained cooling water flowing therethrough which has been found to significantly enhance exhaust gas cooling.
(19) FIG. 9 is a side sectional view of a water can, generally referenced as 30, adapted with vortex generating technology in accordance with the present invention. Water can 30 comprises a water jacketed exhaust component having an exhaust pipe 32, a water jacket 34 disposed in surrounding relation with exhaust pipe 32, and a spray ring 36. The water jacketed exhaust component is typically mounted downstream of the turbocharger and receives exhaust gas and cooling water from the marine engine. Exhaust gas flows through exhaust pipe 32, and cooling water flows through the volume 35 between the outer surface of the exhaust pipe 32 and the inner surface of the water jacket 34. The water is ejected via apertures 38 in spray ring 36. Generally, the spray ring 36 contains a plurality of apertures 38 from which the cooling water is ejected under pressure from the water pump in the form of a spray or stream. A significant aspect of the present invention involves adapting water can 30, and particularly the terminal end of exhaust pipe 32, with a plurality of vortex generating tabs 20 which are angularly spaced so as to define gaps 22. As with the embodiments discussed hereinabove, tabs 20 are angled radially inward so as to interfere with the exhaust flow thereby generating whirling vortex flow to enhance mixing of exhaust gas and cooling water in accordance with object of the present invention.
(20) FIG. 10 is a partial detailed view illustrating vortex flow generated as exhaust gas and entrained cooling water flow past and through vortex generating tabs 20 and gaps 22. As illustrated in FIG. 10 exhaust gas flowing past tabs 20 is induced into a whirling chaotic disruptive flow that has been found to enhance the mixing and absorption of cooling water entrained by the exhaust gas flow. Tabs 20 have upstream facing surfaces that are preferably generally planar, but may further be concave or convex. In addition, the upstream facing surfaces are preferably disposed at a zero-degree pitch about a longitudinal axis so as to avoid imparting an axially spiral flow within the downstream exhaust pipe which could result in centrifugal separation of entrained cooling water from the exhaust gas.
(21) The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.
