Abstract:
The present invention provides a hypersonic jet engine able to start in air-breathing mode, on its own, from zero speed without a compressor. The hypersonic jet engine, known herein as the hyperjet is also able to fly an aircraft at and faster than Mach 6 without using the scramjet method of combustion, while maintaining a fuel economy superior to that of a aircraft utilizing a turbofan engine. The present invention is operable in a pulsejet mode, a ramjet mode, and chemical rocket mode, and utilizes front and back airflow gates driven by DC motors or electromagnetic fields.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to jet engines, and more specifically but not by way of limitation, to a hypersonic jet engine operable in a pulsejet mode, a ramjet mode, and a chemical rocket mode, in part, by utilizing front and rear air flow gates.  
       BACKGROUND  
       [0002]     In the aircraft industry, there is always a desire to improve an aircnifts ability to fly faster, farther and with more fuel efficiency, per passenger. As such, there is a desire in the industry to be able to have supersonic and hypersonic flights, with aircraft that have fuel consumption better than turbofan-propelled jumbo-jet aircraft (whose size is similar to that of a Boeing™ 747).  
         [0003]     The desire and need for improved speed, range and fuel efficiency is not limited to the aircraft industry. As can be appreciated, it also extends into the spacecraft industry.  
         [0004]     Accordingly there is a need for an aircraft engine capable of moving large aircraft at hypersonic speeds while having fuel consumption much lower than that of a turbofan-propelled aircraft of similar size.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a hypersonic jet engine able to start in air-breathing mode, on its own, from zero speed without a compressor. The hypersonic jet engine is further able to fly an aircraft at and faster than Mach 6 without using the scramjet method of combustion, while maintaining a fuel economy equal to or better that that of a turbofan engine. The present invention is operable in a pulsejet mode, a ramjet mode, and chemical rocket mode, and utilizes front and back airflow gates driven by DC motors or electromagnetic fields to regulate the intake and exhaust of the engine. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     A more complete understanding of the present invention may be had by reference to the following Detailed Description and appended claims when taken in conjunction with the accompanying Drawings wherein:  
         [0007]      FIG. 1  illustrates a perspective view of an engine mounted to a wing of an aircraft in accordance with the principles of the present invention;  
         [0008]      FIGS. 2-5  illustrate cross-sectional views of a preferred embodiment of the present invention in various operating modes taken along line A-A of  FIG. 1 ;  
         [0009]      FIG. 6  illustrates a partial cross-sectional side view of the interior of the engine at the combustor ring;  
         [0010]      FIG. 7  illustrates a front view of a preferred embodiment of the present invention; and  
         [0011]     FIG. 8  illustrates a cross-sectional side view of a preferred embodiment of a ramjet combustor.  
     
    
     DETAILED DESCRIPTION  
       [0012]     Referring now to the drawings submitted herewith, wherein various elements depicted are not necessarily drawn to scale, and where like elements in various views are depicted with identical element numbers, and in particular to  FIG. 1 , there is illustrated a perspective view of a preferred embodiment of a hyperjet  100  in accordance with the principles of the present invention. Hyperjet  100  is illustrated attached to the underside of wing  210  of an aircraft  202 .  
         [0013]     Referring now to  FIGS. 2-5 , there is illustrated a side cross-sectional view taken along line A-A of  FIG. 1 , illustrating the interior components of hyperjet  100 . As described in more detail herein, hyperjet  100  is operable in various modes, including a pulsejet mode, a ramjet mode, and chemical rocket mode.  
         [0014]     As illustrated, hypedjet  100  includes an exterior casing  102  for housing the components therein. Disposed within exterior casing  102  is an interior casing and fuel injector housing  104 . Airflow gate assemblies  106  and  108  are also disposed within exterior casing  102 , with airflow gate assembly  106  being positioned at the intake end of hyperjet  100  and airflow gate assembly  108  being positioned at the exhaust end of hyperjet  100 . Airflow gate assemblies  106  and  108  are hollow spheres containing a pipe as wide as the interior diameter of the hypedjet  100 . DC motors  110  and  112  are connected to airflow gates assemblies  106  and  108  respectively. A ramjet combustor ring  114  is positioned proximate to airflow gate assembly  106 , with ramjet combustor ring  114  made up of a plurality of ramjet burners  116 .  
         [0015]     Airflow gate assembly  106  includes gate  120  and a flow path  124 , and airflow gate assembly  108  includes gate  126  and flow path  130 .  
         [0016]     In pulsejet mode, airflow gate assemblies  106  and  108  facilitate complete combustion within hyperjet  100 , with airflow gate assemblies  106  and  108  being open and closed by DC motors  110  and  112 . Airflow gate assemblies  106  and  108  are configured in a piped sphere configuration, which does not produce unnecessary shape changes in movement. This helps to facilitate supersonic flight as a result of the drag/shockwave reduction due to the shapes of the airflow gate assemblies  106  and  108 . It is comtemplated that the airflow gate assemblies  106  and  108  could be either pilot or computer controlled. This allows for a more accurate account for ambient air pressure and temperature changes during flight. Upon being exhausted from airflow gate  108  through supersonic nozzle  118 , the combusted gas pressure is to be as close as possible to ambient air pressure. This facilitates the avoidance of shockwave formation at the rear of hyperjet  100  at supersonic speeds.  
         [0017]     Referring now to  FIG. 6 , there is illustrated a partial cross-sectional side view of the interior of hypejet  100  behind airflow gate  106  showing airflow through and about hyperjet  100  at combustor ring  114 . As illustrated, a portion of airflow  300  enters the main burner  200  of hyperjet  100 , while another portion  302  of air flow  300  enter the ramjet burners of ramjet combustor ring  114 . Fuel Injectors  132  inject and mix fuel with airflow  302  in each of the ramjet burners  116  (see  FIG. 7 ) of ramjet combustor ring  114 . Airflows  302  and  300  then flow towards the exhaust of hyperjet  100 .  
         [0018]     Referring now to  FIG. 7 , there is illustrated a frontal view of hyperjet  100  with airflow gate  106  in the open position such that flow path  124  permits airflow into hyperjet  100 . As illustrated, when airflow gate  106  is in the open position, airflow is permitted to enter both the ramjet combustor ring  114  and the center or main burner portion  200  of hyperjet  100 . DC motor  110  is configured within hyperjet  100  to operate the opening and closing of airflow gate  106 . Similarly, DC motor  112  is configured within hyperjet  100  to operate the opening and closing of airflow gate  108 .  
         [0019]     Referring now to  FIGS. 6 and 7 , combustor ring  114  is comprised of a collective of ramjet burners or combustors  116 . Ramjet combustors  116  function only when hyperjet  100  is operating in ramjet mode. When operating in ramjet mode, hyperjet  100  has a performance increase similar to the performance increase offered by the turbofan over the turbojet. In this preferred embodiment, the number of ramjet combustors  116  is always an even number; with the ramjet combustors  116  functioning in symmetrically oriented pairs in order to keep the overall airflow direction parallel to the direction of hyperjet  100 .  
         [0020]     Referring now to  FIG. 8 , there is illustrated a sectional side view of a ramjet burner  116  of ramjet combustor ring  114 . As illustrated, casing  134  generally tapers from each end of ramjet burner  116  towards the center of ramjet burner  116 , forming a throat portion  136 . It is at the throat portion  136  where the fuel injection and combustion take place in ramjet burner  116 . Arrow  304  illustrates typical airflow through ramjet burner  116  during operation.  
         [0021]     As mentioned herein, hyperjet  100  is operable in various modes, including a pulsejet mode, a ramjet mode, and chemical rocket mode. Referring now to  FIGS. 1-8 , a more detailed description of each of these modes will now be described.  
         [0022]     When operating in pulsejet mode, first airflow gates  106  and  108  are both closed (See  FIG. 2 ), whereby air is enclosed in the main burner portion  200  of hypedjet  100 . Fuel is then injected and detonated in the main burner portion  200  of hypedjet  100 , creating the pulse. The main burner portion  200  of hypersonic engine  100  acts as a close-volume pressure vessel. Then gate  108  open, while gate  106  remains closed (See  FIG. 3 ). As a result of the detonation of the fuel injected into the main burner portion  200  of hypersonic engine  100  and the pressure created therein, the high-temperature and high-pressure is then exhausted from hyperjet  100  through supersonic nozzle, creating thrust.  
         [0023]     With airflow gate  108  remaining open, airflow gate  106  then opens (See  FIG. 4 ), permitting the influx of air into hyperjet  100  through airflow gate  106 .  
         [0024]     Airflow gate  108 , then closes (See  FIG. 5 ), whereby the main burner portion  200  of hypersonic engine  100  becomes filled with air at the maximum possible pressure (i.e. stagnation). Once filled with air, the cycle repeats.  
         [0025]     Good results have been achieved with the operation of hyperjet  100  in pulsejet mode when both airflow gates  106  and  108  spin at a steady or constant speed.  
         [0026]     When hypedjet  100  is operating in ramjet mode, both airflow gates  106  and  108  are maintained in the open position, such as is illustrated in  FIG. 4 . In ramjet mode, combustion of fuel is carried out in the ramjet burners  116  of ramjet combustor ring  114  (see  FIG. 8 ) instead of in the main burner  200  of hyperjet  100 . At supersonic speeds, incoming air is slowed into ramjet burners  116  to Mach 1 and gains pressure and temperature in the process. The incoming air reacts with the fuel at Mach 1, is combusted and then exhausted into the main burner area  200  at the same speed as the incoming air (See  FIG. 6 ). This keeps very high pressure and temperature differences from the incoming air. Good results have been achieved by maintaining straight orientation of the exhaust gas by using ram et burners  116  in pairs opposite each other. The incoming air  300  becomes mixed with the high pressure-and-temperature gas  302  and then becomes exhausted such that the exhaust pressure matches the ambient air pressure at an exhaust speed/temperature combination which creates the desired sufficient thrust. In this embodiment, only 20% of the incoming air is burned, which accomplishes about 80% fuel savings over existing ramjets.  
         [0027]     When hyperjet  100  is operating in chemical rocket mode, airflow gate  106  is maintained in the closed position, while airflow gate  108  is maintained in the open position (See  FIG. 3 ). In chemical rocket mode, an independent air/oxygen supply is required as airflow gate  108  is in the closed position, inhibiting air intake into jet engine  100 . In this embodiment, hyperjet  100  can be switched to chemical rocket mode at any speed. Hyperjet  100  can be switched from rocket mode to pulsejet mode if the speed is below Mach 1.85. Hyperjet  100  can be switched to ramjet mode if the speed is above Mach 2. Hyperjet  100  can be switched from chemical rocket mode to either ramjet mode or pulsejet mode if the speed is at or between Mach 1.85 and Mach 2.  
         [0028]     It is contemplated to be within the scope of this invention that the hyperjet  100  described herein is not limited to use on aircraft, but could also be used in other type of crafts and vehicles, such as, but not limited to speedboats.  
         [0029]     The following illustrates the mathematical model of the operation of hyperjet  100 :  
         [0030]     It is noted that only metric units of measure are being used.  
         [0031]     Nomenclature:  
         [0000]     Symbol Meaning  
         [0000]    
       
          f Stoichiometric fuel-to-air mass ratio.  
          T a  Actual ambient temperature.  
          T 0a  Tea Total (stagnation) ambient temperature.  
          T 04  Maximum (stagnation) temperature generated by combustion.  
          Q R  Fuel heating value; average 45 MJ/kg for fuel “JP4”.  
          c p  Specific heat of air at constant pressure; 1003.5 J/(kg*K)  
          c v  Specific heat of air at constant volume; 716.8 J/(kg*K)  
          R Perfect gas constant; 287 J/(kg*K)  
          H R  Specific heat ratio of air; 1.4 ambient; 1.36 within (and ideal case for) nozzle.  
          M Flight Mach (matches speed of aircraft).  
          M e  Exhaust Mach upon leaving the nozzle.  
          v Speed of aircraft (flight speed/airspeed).  
          V e  Exhaust speed upon leaving the nozzle.  
          A e  Cross-sectional area of the end of the supersonic nozzle.  
          T e  Exhaust temperature upon leaving the nozzle.  
          p a  Ambient pressure (1 atmosphere at given altitude).  
          p e  Exhaust pressure upon leaving the nozzle.  
          p 06  Maximum (stagnation) pressure generated by combustion.  
          p 0a  Total (stagnation) pressure before combustion.  
          ma Mass flow rate of air only (in ramjet mode), and of exhaust only (in pulsejet mode).  
          F/m a  Specific thrust. Special unit of measure: “(newton of thrust) per (kilogram per second of exhaust gas)”.  
          TSFC Specific fuel consumption. Special unit of measure: “(kilogram per second of fuel) per (newton of thrust)”.  
       
     
         [0054]     Formulas Used in Calculations  
         [0055]     1. Regarding fuel-to-air ratio and exhaust temperature:  
         [0000]     Assumptions:  
         [0000]    
       
          1. Within ramjet combustion, total pressure changes only once;  
          2. Pulsejet combustion occurs in a constant volume. 
 
 Formula for Ramjet Mode:
 
 f =(( T   04   /T   0a )−1)/(( Q   R /( c   p   *T   0a ))−( T   04   /T   0a ))
 
 Formula for Pulsejet Mode:
 
 f =(( T   04   /T   0a )−1)/(( Q   R /( c   v   *T   0a ))−( T   04   /T   0a ))
 
          2. Regarding Exhaust Mach:
 
 M   e   2 =(2/( H   R −1))*((1+(( H   R −1)/2)* M   2 )*(((p 06   /p   0a )*( p   a   /p   e )) (H   R   −1)/H   R   −1)) 
 
          3. Regarding Exhaust Speed:
 
 v   e   =M   e *(( H   R   *R*T   04 )/(1+( Me   2 *(( H   R −1)/2)))) 0.5 
 
          4. Regarding Specific Thrust: 
 
 Gross (Ignoring Speed of Aircraft):
 
 F/m   a =( v   e *(1+ f ))+(A e *( p   e   −p   a )/ m   a )
 
 Net (Accounting for Speed of Aircraft):
 
 F/m   a =( v   e *(1+ f ))− v +( A   e *( p   e   −p   a )/ m   a )
 
          5. regarding specific fuel consumption:
 
 TSFC=f /( F/m   a )
 
 Pulsejet Mode Behavior at Take-off: 
 
          Environment: T a =290 K, p a =101325 P a , T 04 =2000 K, air density=1.225 kg/m 3 .  
          Before first pulse: p 02 =p a , T 02 =T a  (no speed yet).  
          On first pulse:  
          Combustion (from formula 1): f=0.028  
          Assuming perfect gas behavior: (p 06 /p 0a )=(T 06 /T 0a ), so p 06 =698793.1 Pa  
          To avoid shock formation at exhaust, exhaust pressure must (ideal case) equal ambient pressure, so:  
          Exhaust Mach (from formula 2): M e =1.9253  
          Exhaust speed (from formula 3): v e =1317.43 m/s  
          Gross specific thrust (from formula 4): F/m a =1354.32 N/(kg/s)  
          Specific fuel consumption (from formula 5): TSFC=2.067*10 −5  (kg/s)/N  
          Comparison: Typical turbojet TSFC at take-off is 7*10 −5  (kg/s)/N and typical high bypass turbofan TSFC at take-off is 1.5*10 −5  (kg/s)/N.  
          Estimating main burner dimensions for 1 MN (same as 224719 LBS) thrust at 200 pulses/second at take-off:  
          Exhaust m a =Thrust/(F/m a) =738.38 kg/s, therefore 3.69 kg of exhaust are required from each pulse. 
 
 Only the air which is initially enclosed in the main burner at environment air density is exhausted in each pulse, so the main burner required volume is 3.013 m 3 ; if choosing a main burner length of 2 m, then the internal cross-sectional area is 1.5065 m 2 , so the main burner internal radius is 0.7 m. 
 
 Pulsejet Mode Behavior at Mach 2: 
 
          Environment (from Reference 1, appendix III):  
          Altitude=10 km (given), v=599.064 m/s (derived),  
          T a =223.252 K, p a =26500 Pa, T 04 =2000 K, air density=0.41351 kg/m 3 . 
 
 Before the air enters main burner (from Reference 2, table A2): 
 
          p 0a =207355.2426 Pa 
 
 Due to a slight-vacuum effect created by each pulse plus airflow buildup on the front flow gate (when closed), the maximum possible pressure before combustion is 2* p 0a =414710.4852 Pa, but total temperature stays constant (401.85 K). 
 
          Combustion from formula 1): f=3.154*10 −4    
          Assuming perfect gas behavior: (p 06 /P 0a )=(T 06 /T 0a ), so p 06 =2064006.39 Pa 
 
 To avoid shock formation at exhaust, exhaust pressure must (ideal case) equal ambient pressure, so: 
 
          Exhaust Mach (from formula 2): M e =3.4642  
          Exhaust speed (from formula 3): v e =1721.775 m/s  
          Net specific thrust from formula 4): F/m a =1123.25405 N/(kg/s)  
          Specific fuel consumption from formula 5): TSFC=2.808*10 −7  (kg/s)/N  
          Comparison: The most efficient turbofans to date, used on aircraft Boeing 777™, have a TSFC of 10 −6  (kg/s)/N. 
 
 Ramjet Mode Behavior at Mach 2: 
 
          Environment: Altitude=10 km (given), v=599.064 m/s (derived), T a =223.252 K,  
          p a =26500 P a ,  
          T 04 =2500 K, air density=0.41351 kg/m 3 . 
 
 Within One Small Combustor: 
 
          Before air entry:  
          p 0a =207355.2426 Pa and T 0a =401.85 K  
          Combustion (from formula 1): f= 0 . 04955   
          Assuming perfect gas behavior: (p 06 /p 0a )=(T 06 /T 00a ), SO p 06 =2064006.39 Pa 
 
 To ensure that the air coming into the main burner does not change direction and/or speed upon mixing with the exhaust from the small combustors (herein described as the ramjet burners  116 ), the exhaust speed from the small combustors must equal the speed of the main burner airflow: 
 
          v e(combustor) =599.064 m/s. This leaves a lot of high pressure and temperature (from the small combustors&#39; exhaust) to mix with (thus increasing the overall pressure and temperature of) the airflow in the main burner, so:  
          Exhaust Mach (from formula 2): M e(combustor) =0.6276  
          Exhaust pressure (from Reference 2, table A2): p e(combustor) =1582881.547 Pa  
          Exhaust temperature (from Reference 2, table A2): T e(combustor) =2317.44 K 
 
 Within Main Burner Combustion Occurs in Small Combustors Only): 
 
          Assumption: Total projected area of all small combustors is 20% of main burner cross-sectional area, therefore airflow behavior resembles that of a “turbofan with bypass ratio of 4 and mixed airflows”, so:  
          Mean pressure (not stagnation) in main burner becomes 337776.31 Pa  
          Mean temperature (not stagnation) in main burner becomes 642.09 K  
          Speed of sound in main burner from formula 3) is 507.93 m/s and Mach of mixed airflow is 1.1794 upon completing the mixing process, so from Reference 2, table A2: p 0(exit) =798090.605 Pa and T 0(exit) =820.9 K. Now exit pressure must match ambient pressure, so p(exit)/p 0 (exit)=0.332, so:  
          Exhaust Mach (from formula 2): M e =1.365  
          Exhaust temperature (from Reference 2, table A2): T e =598.04207 K  
          Exhaust speed (from formula 3): v e =659.5 m/s  
          Net specific thrust (from formula 4): F/m a =665.5307 N/(kg/s)  
          Specific fuel consumption ( from formula 5): TSFC=1.489*10 −5  (kg/s)/N  
          Given the previously estimated dimensions, thrust in ramjet mode at Mach 2 is 248368 N (same as 55813 LBS).  
          Comparison: At Mach 2 flight speed, existing ramjets have an average TSFC of 6*10 −5  (kg/s)/N and turbojets have an average TSFC of 3.5*10 −5  (kg/s)/N. 
 
 Ramjet Mode Behavior at Mach 6: 
 
          Environment: Altitude=10 km (given), v=1797.192 m/s (derived),  
          T a =223.252 K, p a =26500 P a ,  
          T 04 =2500 K, air density=0.41351 kg/m 3 . 
 
 Within One Small Combustor: 
 
          Before air entry (from Reference 2, table A2):  
          p 0a =4184139 Pa and T 0a =1912.685 K  
          Combustion (from formula 1): f=0.01387  
          Assuming perfect gas behavior: (p 06 /p 0a )=(T 06 /T 0a ), so p 06 =54719071.62 Pa 
 
 To ensure that the air coming into the main burner does not change direction and/or speed upon mixing with the exhaust from the small combustors, the exhaust speed from the small combustors must equal the speed of the main burner airflow: 
 
          V e(combustor) =1797.192 m/s. This leaves a lot of high pressure and temperature (from the small combustors&#39; exhaust) to mix with (thus increasing the overall pressure and temperature of) the airflow in the main burner, so:  
          Exhaust Mach (from formula 2): M e(combustor) =2.86  
          Exhaust pressure (from Reference 2, table A2): p e(combustor) =18402023.8 Pa  
          Exhaust temperature (from Reference 2, table A2): T e(combustor) =948.425 K 
 
 Within Main Burner (Combustion Occurs in Small Combustors Only): 
 
          Assumption: Total projected area of all small combustors is 20% of main burner cross-sectional area, therefore airflow behavior resembles that of a “turbofan with bypass ratio of 4 and mixed airflows”, so:  
          Mean pressure (not stagnation) in main burner becomes 3701604.76 Pa  
          Mean temperature (not stagnation) in main burner becomes 368.3 K  
          Speed of sound in main burner (from formula 3) is 379.15 m/s and Mach of mixed airflow is 4.74 upon completing the mixing process, so from Reference 2, table A2: p 0(exit) =143473052.7 Pa and T 0(exit) =2022.85 K. Now exit pressure must match ambient pressure, so p (exit) /p 0(exit) =1.847*10 (−4) , so:  
          Exhaust Mach (from formula 2): M e =7.4  
          Exhaust temperature (from Reference 2, table A2): T e =1710.077 K  
          Exhaust speed (from formula 3): v e =6045.747 m/s  
          Net specific thrust (from formula 4): F/m a =6062.518 N/(kg/s)  
          Specific fuel consumption (from formula 5): TSFC=4.5756*10 −7  (kg/s)/N  
          Given the previously estimated dimensions, thrust in ramjet mode at Mach 6 is 6787387.9 N (same as 1525255.7 LBS).  
          Comparison: At Mach 6 flight speed, existing ramjets have an average TSFC of 2.5*10 31 5  (kg/s)/N.  
       
     
         [0130]     The following two references were referred to in working out the above: 
    1. P. Hill, C. Peterson: Mechanics and Thermodynamics of Propulsion, 2nd edition Addison-Wesley Publishing Company, 1992 ISBN 0-201-146592     2. M. Saad: Compressible Fluid Flow Prentice Hall, Inc., 1985 ISBN 0-13-163486    
 
         [0133]     In the preceding detailed description, reference has been made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments, and certain variants thereof, have been described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other suitable embodiments may be utilized and that logical changes may be made without departing from the spirit or scope of the invention. The description may omit certain information known to those skilled in the art. The preceding detailed description is, therefore, not intended to be limited to the specific forms set forth herein, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents, as can be reasonably included within the spirit and scope of the appended claims.