US3048137A

US3048137A - Discharging exhaust products from a torpedo

Info

Publication number: US3048137A
Application number: US659445A
Authority: US
Inventors: Girard L Calehuff
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-05-17
Filing date: 1957-05-17
Publication date: 1962-08-07
Anticipated expiration: 1979-08-07

Description

Aug. 7, 1962 G. CALEHUFF DISCHARGING EXHAUST PRODUCTS FROM A TORPEDO Filed May 17, 1957 G/RARD L. CALEHUFF IN V EN TOR.

BY JzM/LQ 241% A T TORNEYS 3,b48,l37 Patented Aug. 7, 1962 3,048,137 DISCGING EUST RR'DDUCTS FRQM A TGRPEDO This invention relates generally to torpedoes and it has particular reference to certain structural features for discharging exhaust products from a propeller driven torpedo.

For torpedoes provided with a turbine propulsion motor it has been the conventional practice to exhaust the turbine gases through the center of the propeller shaft, thereby requiring complicated and expensive mechanism for the discharging of the exhaust products in this manner. Previous attempts to place exhaust ports in the torpedo tail cone forwardly of the propeller have resulted in instability of the torpedo and the provision of an expansion chamber or the like rearwardly of the torpedo propeller places serious limitations on the form and operation of the expansion chamber and often prohibits conventional handling and/or firing of the torpedo, not to mention the fact that it still requires the complicated and expensive mechanism referred to hereinabove necessary to exhaust the turbine exhaust products through the propeller shaft or shafts.

It is an object of the invention to provide a new and novel means for exhausting turbine gases in a torpedo.

Another object of the invention is the provision of exhaust means forward of the propeller whereby the ex- Must products of the turbine propulsion motor may be circumferentially exhausted in small bubbles at such a rate as to not create an undue back pressure on the turbine and at such a velocity that the bubbles'as they progress upwardly will substantially remain within the boundary layer which surrounds the torpedo when in motion thereby not affecting the efficiency of the propeller.

A further object of the invention is the provision of a new and novel means for exhausting turbine exhaust gases from a torpedo whereby the necessity of complicated and expensive mechanisms required by the conventional method of exhausting such gases through one or more hollow propeller shafts may be eliminated.

These and other objects and features of the invention, together with their incident advantages will be more readily understood and appreciated from the following detailed description of a preferred embodiment thereof selected for purposes of illustration and shown in the accompanying drawing, in which:

FIGURE 1 is a longitudinal sectional view of the tail cone of a torpedo constructed in accordance with the principles of the invention;

FIGURE 2 is a cross sectional view taken on line 2-2 of FIGURE 1.

Torpedoes of conventional design with which the invention finds its greatest utility are commonly referred to as steam torpedoes and are generally divided into a plurality of longitudinal sectional components which are joined by water tight clamping rings. These sections generally comprise a warhead which is the forward extremity, an air flask disposed rearwardly of the warhead, an afterbody section which may house certain control components and the like and a tail cone which carries the turbine propulsion motor and associated shafting, the propeller, and the horizontal and vertical control surfaces and rudders.

With reference now to FIGURE 1, there is shown a tail cone 10 as referred to hereinabove having a propeller 11 mounted in the conventional manner at its rearmost extremity, a propeller shaft 12 disposed and supported within the tail cone ill in the conventional manner for rotatably driving the propeller 11 and a conventional torpedo turbine propulsion motor 13 connected in driving relationship with the propeller shaft 12 to secure the desired rotational speed of the propeller 11. An outer covering 14 of metal or the like and a bulkhead 15 provide means for rigidly supporting the propulsion motor in the conventional manner. Attached to the rear periphery 16 of the metal skin 14 as by continuous welds 17 to form Water tight joints is a wall or bulkhead of considerable rigidity and strength forming a forward wall 18 of a plenum or expansion chamber 19, said wall 18 being provided with an axial passage 21 of such size as to freely receive the propeller shaft 12. A plurality of radially disposed ribs 22 are welded to the metal skin 14 and the Wall 13 to provide additional stiffness to the wall and to reduce any flexing thereof. A turbine exhaust conduit 23 is connected between the turbine exhaust outlet 24 and a passage 25 in the forward wall 18 whereby the turbine exhaust products may be directed into the plenum or expansion chamber 19 disposed intermediate the turbine propulsion motor 13 and the propeller 11.

The rear periphery 16 of the metal skin 14 forming the outer surface of the forward portion of the tail cone 10 is provided with an enlarged and thickened portion 26 to which the expansion chamber forward wall 18 is attached as by continuous welds 17 at surface 27 and which is further adapted to receive the forward periphery 28 of the expansion chamber outer wall 29 as at groove 31 formed by projection 32. The rear portion of the tail cone is provided with an outer covering 33 of sheet metal or the like attached and formed in the conventional manner and provided at its forward periphery 34 with an enlarged and thickened portion 35 substantially identical to the enlarged portion 26 referred to hereinabove and also provided with a groove 36 formed by projections 37 to receive the rear periphery 38 of the expansion chamber outer wall 29. A rear wall or bulkhead forming the rear Wall 39 of the expansion chamber 19 is attached to surface 41 as by continuous welds 42 and is provided with an axial passage 43 having a diameter substantially equal to the axial passage 21 in the expansion chamber forward Wall 1%. Radial ribs 44 are attached to the outer covering 33 and the rear wall 39 as by welding to strengthen the rear wall and to prevent movement or vibration thereof, Disposed between the expansion chamber forward wall 18 and rear wall 39 is an annular inner wall 45 having an inside diameter preferably greater than the diameter of the axial passages 21-43 and rigidly attached to the forward and rearward expansion chamber walls 18-39 at its forward and rearward periphery 46-47 as by welding or the like. The annular inner wall 45 is of such thickness and diameter as to provide a substantially non-flexible connection between the expansion chamber forward wall 18 and rearward wall 39 and provided with an inside diameter such that electrical conduits and/or rudder operating mechanisms or the like may be placed in operational communication with the rear portion of the tail cone without interfering with or being damaged by rotation of the propeller shaft 12. If desired walls 18-39 and their respective axial passages 21-43 may be adapted to receive bearings in which the propulsion shaft may be journalled.

A comically shaped expansion chamber outer wall 29 surrounding and disposed away from the annular inner wall 45 and forming a smooth continuation of the tail cone outer surface is securely attached at its forward and rearward periphery 28-37 to the projections 33-37 as by screws 48 or the like and provide the means for exhausting the turbine exhaust products as and for the purposes hereinafter described. The expansion chamber outer wall 29 preferably extends circumferentially around serene? the center portion of the tail cone and is comprised of a porous or foraminous material such as for example compacted fibre glass, sintered metallic material or the like having a large number of foramina 39 per unit area. Since the expansion chamber outer wall 29.is subjected to only minor stresses in actual service it need not be structurally strong thereby allowing a high concentration of foramina which results in a practically operative exhaust system forwardly of the propeller. As used herein, a foramina is defined to be a more or less transversely disposed passage in the expansion chamber outer wall 29 of such diameter as to allow the expulsion of exhaust gases there through in a small column or a series of minute bubbles. For most satisfactory operation the expansion chamber outer wall 29 should contain a high concentration of foramina 30 per unit area, there being a substantially uniform distribution thereof over the entire outer wall.

Horizontal fins 49 and vertical fins 51 having respectively depth and steering rudders 52--53, there being two fins in each horizontal and vertical group and the pairs of each group being arranged in 180 relation, are welded longitudinally of the tail cone It) at their forward and rearward portions 54-55, the inner surface 56 of the middle portion being preferably disposed away from and above the expansion chamber outer wall 29 to allow the exhausting of the turbine exhaust products through the portion of the outer wall that would normally be covered by the fins. However, it is to be noted that if sufficient area is made available in the manner hereinafter described the middle innerportion of the fins may be adjacent to and in contact with the expansion chamber outer wall. To secure structural rigidity the fins may be fabricated of a plurality of ribs shaped to the cross sectional configuration of the fins and over which a two piece shaped sheet metal covering butt jointed and welded along the fin edge, is secured. The fins may extend over roughly three-quarters of the length of the tail cone beginning at the forward extremity thereof, and by reason of their rigid construction and the secure attachment to the tail cone at their forward and rear portions function as reinforcing elements in cooperation with the expansion chamber forward wall 18, annular inner wall 45 and rear wall 39 to impart both longitudinal and lateral stiffness to the tail cone thereby resulting in a structure allowing the use of a structurally weak expansion chamber outer wall 29.

The efficiency of the operation of the expansion or plenum chamber 19 basically depends upon the ratio of the rate of expulsion of exhaust gases through the expansion chamber outer wall 29 to the rate at which the exhaust gases are exhausted into the expansion chamber 19; and the concentration and distribution of the foramina in the expansion chamber outer wall 29. The requisite concentration and distribution of foramina per unit area of the outer wall is controlled by the selection of a suitable material such as for example porous fibreglass or the like and the ratio referred to hereinabove may be determined by the longitudinal location of the expansion chamber 19 in the tail cone 10 and the longitudinal distance between the forward and rearward walls 18-39 of the expansion chamber, the latter obviously resulting in a determination of the total area of the expansion chamber outer wall 29.

The determination indicated immediately hereinabove must be such that the exhaust gases from the turbine will be exhausted through the expansion chamber outer wall 29 in minute bubbles evenly and circumferentially and a relatively low velocity, the velocity being such that the thickness in a radial direction of the rearwardly moving bubbles will be of an order not greater than the boundary layer and preferrably not greater than the laminar sublayer of water that surrounds the torpedo when in actual service. If the thickness of the rearwardly moving exhaust gases is of an order less than the boundary layer surrounding the tail cone the efiiciency of the propeller will be substantially unaffected since the bubbles will flow over and past the propeller hub 57 and a portion of the root section 58 of the propeller blades that are not effective in contributing to the thrust developed by the propeller.

As may now be obvious, in view of the foregoing description, the exhaust products of the turbine are directed into the expansion chamber 19 via the conduit 23 connecting the exhaust outlet 24 of the turbine 13 and the forward wall 18 of the expansion chamber. When the pressure in the expansion chamber 19 becomes sutliciently high, but below that which would amount to an undesirable back pressure on the turbine, the exhaust gases will be uniformly forced through the outer wall in the manner described and exhausted at a velocity insufiicient to cause them to be projected past the boundary layer and will travel rearwardly remaining substantially within the boundary layer thereby passing the rudders 5253 and propeller 11 without creating any substantially undesirable effects.

While the present invention has been described in its preferred embodiment it is realized that modifications may be made, and it is desired that it be understood that no limitations upon the invention are intended other than may be imposed by the scope of the appended claims.

Having now disclosed my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In exhaust means for a torpedo having a turbine propulsion motor and a propulsion shaft mounting a propeller for propelling the torpedo the combination comprising: an expansion chamber disposed between the propeller and the turbine, said expansion chamber comprising a forward wall, a rearward wall and a longitudinally disposed annular inner wall integral with and supported by said forward and rearward walls and accessible at both ends to freely receive said propulsion shaft; conduit means for directing the exhaust gases of said turbine into said expansion chamber; and a porous expansion chamber outer wall disposed away from and enclosing said annular inner wall whereby the gases exhausted into said expansion chamber will be exhausted through said outer wall, said outer wall having an area and porosity whereby said gases will be substantially circumferentially exhausted through said wall at a low velocity and at a rate sufiicient to prevent a substantial back pressure on said turbine.

2. In exhaust means for a torpedo having a turbine propulsion motor and a propulsion shaft mounting a propeller for propelling the torpedo the combination comprising: an expansion chamber disposed between said propeller and said turbine, said expansion chamber comprising a forward wall having a first axial opening and integral at its outer periphery with said torpedo, a rear wall having a second axial opening concentric with said first opening and integral at its outer periphery with said torpedo, and a longitudinally disposed annular inner wall disposed between said forward wall and said rear wall and integral therewith at said first and second openings; first support means forward of said forward Wall and integral therewith; second support means rearward of said rear wall and integral therewith, said forward wall, rear wall and annular inner wall being disposed and adapted to provide a rigid unit, said first and second openings and said annular inner wall being further adapted to rotatably receive said propulsion shaft; conduit means for directing the exhaust gases of said turbine into said expansion chamber; and a porous expansion chamber outer wall disposed away from and enclosing said annular inner wall whereby the gases exhausted into said expansion chamber will be exhausted through said outer wall, said outer wall having an area and porosity whereby said gases will be substantially circumferentially exhausted through said wall at a low velocity and at a rate suflicient to prevent a substantial back pressure on said turbine.

3. In exhaust means for a torpedo having a gas driven turbine propulsion motor and a propulsion shaft mounting a propeller for propelling the torpedo the combination comprising: a forward wall having a first axial opening and integral at its outer periphery with said torpedo; a rear wall having a second axial opening concentric with said first opening and integral at its outer periphery with said torpedo; a longitudinally disposed annular inner wall disposed between said forward wall and said rear wall and integral therewith at said first and second openings; first support means forward of said forward wall and integral therewith; second support means rearward of said rear wall and integral therewith, said forward wall, rear wall and annular inner wall being disposed and adapted to provide a rigid unit, intermediate said turbine and said propeller, said first and second openings and said annular inner wall being further adapted and disposed to rotatably receive said propulsion shaft; conduit means conmeeting said turbine and said forward Wall whereby the exhaust gases from said turbine may be exhausted rearwardly through said forward wall; and a porous outer wall carried by said torpedo and disposed away from and enclosing said annular inner wall whereby the turbine exhaust gases will be exhausted from the torpedo through said outer wall, said outer Wall having an area and high concentration of foramina per unit area whereby said gases will be substantially circumferentially exhausted through said wall at a low velocity and at a rate sufficient to prevent a substantial back pressure on said turbine.

4. The combination as described in claim 3 wherein said outer wall is composed of a foraminous fiberglass composition.

5. The combination as described in claim 4 wherein said foraminous outer wall contains foramina of such size, distribution and number whereby the exhaust gases are evenly and circumferentially exhausted in minute bubbles at a velocity such that they remain substantially within the fluid boundary layer surrounding said outer wall when the torpedo is in motion.

6. The combination as described in claim 5 additionally including a plurality of rigid radially extending and longitudinally disposed stabilizer fins having a front portion, a middle portion and a rear portion, said front portion being fixedly attached to said torpedo forwardly of said forward wall, said middle portion being disposed adjacent said outer wall and said end portion being fixedly attached to said torpedo rearwardly of said rear wall whereby movement of said rear wall with respect to said forward wall is substantially prevented.

References Cited in the file of this patent UNITED STATES PATENTS 1,541,689 Davis June 9, 1925