BACKGROUND OF THE INVENTION
1. Technical Field
This invention generally relates to a turbine drive and more particularly relates to a turbine hydrojet drive which is particularly adapted for operation in water.
RELATED ART
Gas turbine drives have reached a high degree of development and are utilized in many applications such as airplane and boat propulsion systems. These vehicles are often propelled by a gas turbine drive operating in the atmosphere. Such drives intake air, compress the air, heat the air and exhaust it thus producing a forward thrust. Relatively high efficiencies are obtained in the order of 85 to 99% as compared to air propeller systems which exhibit in the order of 46% efficiency.
Heretofore, turbine drives have not functioned effectively in a relatively incompressible liquid such as water. Due to the incompressibility of water, presently known turbine drives have not produced sufficient fluid compression to generate acceptable thrust levels. In water, propeller systems have generally been used which exhibit low efficiencies in the order of 7 to 9%. The drag and high resistance which the water exerts on the rotating propeller greatly limits the efficiencies obtainable. To provide one solution to this problem, it has been suggested that a turbine drive operating in water be provided with a compressible fluid by injecting helium gas into the turbine drive. The helium is compressed along with a quantity of intake water, the water-helium fluid is exhausted and the expanding fluid produces thrust. Such systems are expensive due to the required external source of helium as well a being large and cumbersome. As will be more fully described, this invention provides a turbine hydrojet drive which is operable while fully immersed in water. It is operable without the introduction of any external gas supplies and produces thrust at high efficiencies in the order of 90 to 95%.
SUMMARY OF THE INVENTION
Described is a turbine hydrojet drive as well as the method of operation thereof. The turbine hydrojet drive includes an elongated housing adapted to be fixed to a vehicle. The housing defines an intake section, a compressor section and an exhaust section. A drive shaft is positioned for rotation within the housing. The compressor section includes a first turbine assembly having a first compressor rotor fixed to the drive shaft and a plurality of first rotor blades projecting radically outwardly from the drive shaft. The first compressor rotor blades have a water pitch adapted for rotation in a first direction so as to bring a predetermined quantity of water into the housing. The first turbine assembly additionally includes a first stator with the outwardly projecting ends of the stator vanes fixed to the inner wall of the housing and serving to redirect the circular flow of water from the first compressor rotor into a fluid flow generally along the axis of the drive shaft. The exhaust section includes a buffer zone defining a cross-sectional area so that the pressure of the fluid passing therethrough is reduced and correspondingly the back pressure on the first turbine assembly is reduced.
A method of operation of a turbine hydrojet drive is described including the steps of drawing water into an elongated cylindrical housing having a central axis, rotating the water at a very high rate of speed and forcing the water against the walls of the housing and against the first stator vanes. A portion of the water thereby separates into its gaseous components and the water-gas fluid is compressed. The flow path of the water-gas fluid is reoriented generally along the axis of the housing. The fluid pressure is decreased within a buffer zone and then exhausted from the nozzle producing forward thrust.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a turbine hydrojet drive embodying certain features of this invention with a portion removed for clarity of illustration.
FIG. 2 is a full section view of the drive of FIG. 1 taken along the line 2--2.
FIG. 3 is a full section view taken along the line 3--3 of FIG. 2 with a portion removed for clarity of illustration.
FIG. 4 is a full section view taken along the line 4--4 of FIG. 2.
FIG. 5 is a full section view taken along the line 5--5 of FIG. 2.
FIG. 6 is a full section view taken along the line 6--6 of FIG. 2.
FIG. 7 is a full section view taken along the line 7--7 of FIG. 2; and
FIG. 8 is a full section view taken along the line 8--8 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
General
Throughout the following description, the theoretical, physical principles in accordance with which the preferred embodiment appears to operate have been set forth. Although every attempt has been made to describe these physical principles accurately, it may be subsequently determined, based on additional information, that this explanation is not completely accurate. It should be appreciated that the discussion of these physical principles is provided to clarify the theoretical operation of the preferred embodiment and not to limit the scope of the apparatus or method as claimed.
A turbine hydrojet drive 10 is illustrated in FIG. 1 which includes an intake section 12, a compressor section 14 and an exhaust section 16. The intake 12 and compressor 14 sections as well as a portion of the exhaust section 16 are maintained within an elongated generally cylindrically shaped housing 18 with that portion defining the intake section 12 being a uniform cylinder. The inner walls 22 of the housing 18 defining the compressor section 14 display a slight inwardly directed taper of approximately four degrees. This inner wall 22 taper serves to increase the fluid compression within the housing 18 as will subsequently be more fully appreciated. High speed rotational power is provided by an auxiliary, rotary power source 24 coupled by a connecting shaft 26 to the turbine hydrojet drive 10. As illustrated, the housing 18 is mounted upon a vehicle (not shown) by a support strut 28 which is firmly secured to the outer wall of the housing 18 adjacent the compressor section 14. In use, the turbine hydrojet drive 10 is submerged in water while the vehicle (not shown) rides on the surface.
Intake Section
As illustrated in FIG. 2, the intake section 12 of the housing 18 defines an intake cowling 30 the forward edge of which is slightly rounded as at 32 to reduce resistance and introduce minimum turbulence while parting and directing the water into the housing 18. The auxiliary power source 24 is coupled by the connecting shaft 26 to a conically shaped intake drive hub 34 secured to the forward end of a drive shaft 36 mounted for rotation within the housing 18. The intake drive hub 34 is coupled to the connecting shaft 26 by means of a swivel socket 38 and rotates under power provided by the auxiliary power source 24. The shape of the hub 34 is selected to present a low resistance to the inflow of water into the housing 18.
Compressor Section
As illustrated, the compressor section 14 includes first 40, second 42 and third 44 turbine assemblies. Fixed to the drive shaft 36 and positioned adjacent the intake hub 34 is the first turbine assembly 40 which includes a first compressor rotor 46. As particularly shown in FIG. 3, the first compressor rotor 46 has eight equally spaced 48 blades which are fixed to a first rotor hub 50 secured to the drive shaft 36. The inwardly directed ends of each of the first compressor rotor blades 48 has a male bulbroot 52 which mates with a corresponding female bulbroot socket machined into the outer surface of the first rotor hub 50. The leading edges of the rotor blades 48 are tapered following a profile know in the art as a water pitch. The term pitch is used in its conventional sense as a measure of the distance a rotor will travel in one complete revolution in a medium without encountering resistance. Each of the first compressor rotor blades 48 serve to slice and pull water into the turbine drive housing 18. The leading edge 54 of each of the first compressor rotor blades 48 extends slightly beyond the forward edge of the hub 50 and is tapered to define a projecting blunt point. The pitch of the first compressor rotor blades 48 is carefully selected to bring in a predetermined quantity of water necessary for efficient operation while introducing a minimum amount of drag.
Positioned in the direction of fluid flow, as indicated by the arrow 55, immediately behind the first compressor rotor 46 is a first stator 56. As shown in FIG. 4, the first stator 56 includes a hub 58 having a radial bearing 60 through which the drive shaft 36 passes for free rotation therein. The bearings 60 are protected by fluid seals 62. Mounted to the outer surface of the first stator hub 58 are twelve equally spaced first stator vanes 64. Each of the first stator vanes 64 is mounted to the first stator hub 58 by a bulbroot assembly 66. The stator vanes 64 display a relatively flat profile with the leading edge of each vane 64 being on a common plane with the forward surface of the first stator hub 58 and each is secured to the inner wall of the housing 18 by suitable means. It will be appreciated that since the stator vanes 64 are secured to the inner wall of the housing 18 and support the hub 58, the position of the drive shaft 36 is precisely maintained within the housing 18. As illustrated particularly in FIG. 1, the pitch direction of the first stator vanes 64 is opposite to the pitch direction of the first compressor rotor blades 48 in order to straighten the circular flow of the water-gas fluid discharged by the first compressor rotor 46. The vanes 64 redirect the circular flow of the water-gas fluid coming from the first compressor rotor 46 into a flow substantially along the longitudinal axis of the drive shaft 36.
The drive shaft 36 is driven at a high rotational speed and the intake water, which now has a strong circular momentum, is forced outwardly by the first compressor rotor 46 against the inner walls of the housing 18 and against the leading edges of the first stator vanes 64. This force, which is abruptly resisted by the stator vanes 64 and the inner wall of the housing 18, causes a small amount of the water molecules to break down into their constituent parts of oxygen and hydrogen. Thus, due to the centrifugal and axial thrust of the first compressor rotor 46, the water is forced against the walls of the housing 18 and stator vanes 64 reducing a portion of the water to a gas. During testing of a prototype of the turbine drive 10, embodying certain features of this invention, it was found that approximately fifteen percent of the intake water had been broken down into its gaseous components within the first turbine assembly 40 while operating the prototype at approximately 7,500 rpm.
Positioned adjacent and in the direction of fluid flow 55 from the first turbine assembly 40 and receiving the compressed water-gas fluid therefrom is the second turbine assembly 42 comprising a second compressor rotor 68 (FIG. 5) and a second stator 70 (FIG. 6). As illustrated, the second compressor rotor 68 includes fourteen compressor blades 72 mounted to a second rotor hub 74 by bulbroot fasteners 76 with the hub 74 being fixed to the drive shaft 36 for rotation therewith. Since the second compressor rotor blades 72 receive a water-gas fluid with a relatively high gas content, they display a profile known in the art as an air pitch. The air pitch effectively allows the second compressor rotor blades 72 to push the compressed water-gas fluid through the turbine hydrojet drive 10 whereas the first compressor rotor 46 pulls the water into the turbine hydrojet drive 10. The pitch of the second compressor stator blades 72 is considerably greater than the pitch of the first compressor rotor blades 48. The previously mentioned prototype turbine hydrojet drive 10 was constructed with first compressor rotor blades 48 having a pitch of four and a half inches and second compressor rotor blades 72 having a pitch of 14.84 inches. That is, in this prototype, the second compressor rotor blades 72 had a pitch almost three and a half times as great as the pitch of the first compressor rotor blades 48. The water-gas fluid, which has as a generally axially flow pattern from the first stator 56 is again whirled at a high rate of speed by the second compressor rotor 68. Due to the centrifugal forces created, a certain portion of the water is slammed against the inner wall of the housing 18 and the remaining water-gas fluid is forced into the second stator 70.
The second stator 70 includes fourteen equally spaced radially oriented vanes 78 secured to the inner wall of the housing 18. The inwardly extending ends of the second stator vanes 78 are mounted on a hub 80 by means of bulbroot fasteners 82. The drive shaft 36 is supported in the hub 80 by radial bearings 84 protected by a fluid seal 86. It should be noted that the second compressor rotor blades 72 as well as the second stator vanes 78 are shorter than their respective first turbine assembly 40 counterparts due to the previously mentioned four degree taper of the inner walls of the housing 18. As illustrated in FIGS. 5 and 6, the pitch of the second stator vanes 78 is opposite to the pitch of the second compressor rotor blades 72 and therefore redirects the rotating water-gas fluid from the second compressor rotor 68 into a flow pattern having a generally axial orientation. The high speed rotation of the second compressor rotor blades 72 forcefully drives the water-gas fluid against the walls of the housing 18 and into the second stator vanes 78 resulting in the further breakdown of an additional portion of the water into its gaseous components. During an analysis of the previously mentioned prototype, it was determined that approximately fifty percent of the water drawn into the turbine drive 10 had been converted into its gaseous components by the time it had passed through the second turbine assembly 42.
The compressed water-gas fluid from the second turbine assembly 42 is forced into the third turbine assembly 44 which similarly includes a third compressor rotor 88 (FIG. 7) and a third stator 90 (FIG. 8). The third compressor rotor 88 is of similar configuration to the second compressor rotor 68 and includes a rotor hub 92 fixed to the drive shaft 36 for rotation therewith. Projecting radially from the hub 92 and uniformly spaced are sixteen rotor blades 94 mounted by bulbroots 96. As illustrated, the blades 94 have a pitch slightly greater than the pitch of the second compressor rotor blades 72. The previously mentioned prototype included a second compressor rotor 68 with blades 72 having a pitch of 14.84 inches and the third compressor rotor blades 94 having a pitch of 18.25 inches. The increased number of blades 94 and their increased pitch, as compared to the second compressor rotor blades 72, was selected to more efficiently compress the water-gas fluid, with its increased percentage of gas, in the third turbine assembly 44. As mentioned, the walls of the housing 18 taper inwardly and the third rotor compressor blades 94 are slightly shorter than the second rotor compressor blades 72 to accommodate this housing taper. It was found preferable, due to the increased compression of the water-gas fluid as well as the reduced cross-sectional area and volume of the housing 18 in the third turbine assembly 44, to increase the number of blades 94 in the third compressor rotor 88 as compared to the second compressor rotor 68 to more efficiently handle the increased fluid mass. The water-gas fluid is forced by the third compressor rotor 88 into the third stator 90 and outwardly against the inner walls of the housing 18.
As illustrated, the third stator 90 includes sixteen equally spaced vanes 97 the outer ends of which are secured to the inner wall of the housing 18. The pitch of the third stator vanes 97 is opposite to the pitch of the third compressor rotor blades 94. The inwardly directed ends of the third stator vanes 97 are mounted by means of bulbroot assemblies 98 to the surface of a third stator hub 100. The third stator hub 100 includes a radial bearing 104 as well as a front 106 and a rear 108 thrust bearing which are assembled on the end of the drive shaft 36 by means of a threaded end cap 110. A protective seal 112 is positioned on the drive shaft 36 adjacent the front thrust bearing 106. As the water-gas fluid is whirled at a very high rate of speed by the third compressor rotor 88 it is forced against the stator vanes 97 and, in a manner similar to that previously discussed in connection with the first 40 and second 42 turbine assemblies, additional water molecules are broken into their gaseous components. The water-gas fluids circular flow is straightened by the third stator 90 into a substantially axial flow pattern. The compressed water-gas fluid is forced out of the third turbine assembly 44 into the exhaust section 16. With reference to the previously mentioned prototype, it was found that at the output of the third turbine assembly 44, eighty to ninety percent of the intake water had been converted into compressible gas. It should be appreciated that additional turbine sections exceeding the three illustrated may be desirable or even a single turbine assembly may be adequate for the application to which the turbine hydrojet drive 10 is to be used without departing from the scope and spirit of this invention.
Exhaust Section
The exhaust section 16 includes a buffer zone 114 which serves to reduce the back pressure against the third turbine assembly 44 to prevent the water-gas fluids within the buffer zone 114 from being forced back into the third stator 90 which occurrence would greatly decrease the efficiency of the turbine hydrojet drive 10. The inner wall of the housing 18 defining the buffer zone 114 is in the form of a relatively uniform cylinder correspondingly defining a uniform volume. Securely threaded to the outer wall of the housing 18 is a pivot ball swivel extension 116. The inner surface of the pivot ball swivel extension 116 continues the uniform cylindrical shape of the inner wall of the housing 18 contributing to the size of the buffer zone 114. Positioned within the buffer zone 114 is a tail cone 118 having a frustro conical shape with the base of the cone 118 positioned adjacent the third stator 90. Thus, the cross sectional area of the buffer zone 114 increases from the intake end adjacent to the third stator 90 to the discharge end. This volume increase allows the water-gas fluid from the third turbine assembly 44 to expand, and therefore pressure within the buffer zone 114 decreases reducing the back pressure on the third turbine assembly 44. The exhaust from the buffer zone 114 discharges into a nozzle 120. As illustrated, the tail cone 118 is threaded upon an extension of the third stator hub 100 and extends into the nozzle 120.
The nozzle 120 has a tapered conical wall section 122 which has a curved inwardly disposed surface for mating engagement with the pivot ball swivel extension 116 as well as a ring of threads on the outer surface which engage threads on a nozzle retaining ring 124. The retaining ring 124 secures the nozzle 120 to the pivot ball swivel extension 116. The retaining ring 124 secures the nozzle 120 to the pivot ball swivel extension 116. Thus, the inner wall 122 of the nozzle 120 is in the shape of a section of a cone with a decreasing cross-sectional area as the nozzle 120 progresses from the buffer zone 114 to an exhaust orifice 125. The cross-sectional area of the end of the tail cone 118 decreases at a slower rate than the cross-sectional area of the nozzle 120. Thus, the water-gas fluid pressure within the nozzle 120 progressively increases. With respect to the operation of the previously mentioned prototype, a three fold pressure increase was observed within the nozzle 120. The pressurized fluid from the nozzle 120 is directed by a diffuser 126 which is in the form of an outwardly directed taper on the inner wall of the discharge end of the nozzle 120. The diffuser 126 is shaped to direct the water-gas fluid for expansion out beyond the end of the nozzle 120 so that any low pressure vortices created do not produce drag on the housing 18. The nozzle 120 is positioned to divert the exhaust therefrom in the desired direction by loosening the engagement of the nozzle 120 with the retaining ring 124 and pivoting the nozzle 120 about the ball swivel extension 116 to the desired position. Thereafter, the nozzle 120 is secured by tightening the retaining ring 124.
Operation
In operation, the turbine hydrojet drive 10 is submerged in water and the auxiliary power source 24 rotates the drive shaft 36 at a very high speed. The eight blades 48 of the first compressor rotor 46, have a water pitch and pull water into the housing 18 forcing it against the first stator vanes 64 whereupon a portion of the water is broken into its gaseous components. The fluid flow is aligned by the first stator 56 generally along the axis of the housing 18 for introduction into the second compressor rotor 68. Due to the previously mentioned forces abruptly stopping and redirecting the water molecules, the fluid entering the second turbine assembly 42 contains a relatively high gas content allowing the water-gas fluid to be compressed. The second compressor rotor 68, having an air pitch, drives the water-gas fluid into the second stator 70 whereat it is realigned. Additionally, a still greater portion of the water is broken down into its gaseous components. The water-gas fluid, which is under pressure, is forced into the third compressor rotor 88 and the fluid is realigned by the third stator 90. The compressed fluid is forced into the buffer zone 114 whereat the fluid is allowed to slightly expand thus reducing the back pressure on the third turbine assembly 44. The pressurized fluid passes therefrom into the nozzle 120 whereat the fluid is significantly recompressed and finally the compressed water-gas fluid passes through the nozzle 120 producing a thrust which is coupled through the support strut 28 to a vehicle (not shown). Desired vehicle lift is provided by adjusting the position of the nozzle 120 on the pivot ball swivel extension 116 with respect to the housing 18 and locking it in place with the retaining ring 124. During operation of the aforementioned prototype, it was noted that the exhaust from the drive contained gas bubbles which did not escape to the surface of the water. Rather the gasses recombined, in the water behind the nozzle 120, into water. This recombination of the exhaust gasses into water provided an incompressible medium against which the subsequent drive exhaust reacted resulting in improved drive efficiency.
A turbine hydrojet drive 10 and method of operation thereof has been described. Although a single embodiment of the invention has been considered, it will be understood that various changes in form and detail may be made without departing from the scope and spirit of the invention as set forth in the following claims.