GB1605195A - Drive arrangement for underwater craft - Google Patents

Description

(54) A DRIVE ARRANGEMENT FOR UNDERWATER CRAFT 7 9V yS > t (71) We, MESSERSCHMrRr-BOLKOW- BLOHM GESELLSCHAF r MIT DESCHRANKTER HAFTUNG of 8000 Munchen, Western Germany, a company organised and existing under the laws of Western Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:: This invention relates to a driving arrangement for underwater craft, such as torpedos, having a gas generator fed with a two-component propellant which is independent of oxygen from the air from one tank holding liquid fuel and a second tank for holding a liquid oxidizing agent, the propellant gases acting on a single- or multi-stage turbine, and in which water serving as a coolant and an additional operating medium is injected into the hot propellant gases before they reach the turbine. The hot exhaust gas from the turbine pass through a cooler in which the exhaust gases are at least partly condensed before being exhausted externally.

Drives for torpedos should be compact, light in weight, easy to operate, free from gaseous discharges, unaffected by depth of operation, trouble-free, re-usable several times for training purposes and nevertheless powerful and capable of covering a long distance.

Turbine drives fulfil most of these requirements and have compact and relatively simple constructions as well as moderate weight per unit of power.

Turbine drives for torpedos have certain disadvantages such as low efficiency which is affected by depth of operation, the efficiency decreasing with increase of depth. Limits on the rotational speed are set by the resistance of the bearings and turbines wheels at high speeds, and the mechanical load and the thermal load of the gas generator and turbine set limits on the increase in the pressure and/or temperature of the propellant gas. In addition, torpedo drives must operate practically free of gas discharges which form bubbles so that the torpedo is not located by a bubble trail and that sonar target seeking apparatus is not subject to interference.

In one arrangement propulsive gases obtained from catalytically decomposed hydrogen peroxide act on a turbine and the exhaust gases which consist of a mixture of steam and oxygen, are cooled in a heat exchanger, the oxygen is eliminated by combustion or absorption, and the exhaust gases mixed with water enter a water thrust nozzle serving as the actual driving device so that in motion under the water the emergence of gas bubbles which would leave a trail is avoided.

This drive is for use only once and has disadvantages.

The hydrogen peroxide propellant has only an average energy content in relation to density and is only storable under certain conditions.

A special device is also required for the elimination of the oxygen contained in the exhaust gas.

Another system avoids the drawbacks of the foregoing and uses a fuel which consists of liquid hydrogen and liquid oxygen. The cooling of the propulsive gases which occur in the combustion of this high energy propellant system and which are too hot for the turbine uses water obtained from desålhation plant carried on board the water being injected to increase the quantity of propixlsive gas in front of the turbine while the exhaust gas leaving the turbine is at least partly condensed by indirect cooling with sea-water in a heat-exchanger.

Disadvantages are that the propellant system is cryogenic and thus not easily stored and can only be handled with difficulty and the production of the water required for the cooling of the propulsive gases and as an additional operating medium by de-salination of seawater requires a supplementary and comparatively complex apparatus. The heat exchanger also forming an exhaust-gas condenser is complex, insufficiently adaptable to the operating conditions, and also insuffieciently compact.

According to this-invention there is provided a drive arrangement for underwater craft having a gas generator fed with a two component propellant from one tank containing liquid fuel and another tank containing liquid oxidizer, propellant gases acting on a single- or multi-stage power turbine, water being injected into the hot propellant gases before the turbine, and the hot exhaust gas leaving the turbine passing to a cooler in which the exhaust gas is at least partly condensed before discharge externally of the craft, wherein the fuel and oxidizer are subject in use to ambient water pressure, the fuel comprising a hydrocarbon and/or an alcohol and the oxidizer comprising concentrated aqueous perchloric acid solution and/or hydroxyl ammonium perchlorate solution, and the cooler following the turbine comprising a condenser having means for the direct injection of cooling water.

The design of the driving arrangement according to the invention using the foregoing combination of fuel and oxidizing agent, which is known as a high-energy and storable propellant for submarine drives but which because of the high combustion temperature and corrosive nature of the resulting propulsive gases was regarded as unsuitable for turbine drives, makes it possible to dispense with electrolytic sea-Rvater decomposition and gas liquefaction apparatus on board the vessel, to effect tank filling at any desired moment before actual use, and to dispense with costly insulation for the propellant tanks and propellant feed devices which are required when cryogenic propellants are used. It is also possible to use for the oxidizing agent and for the fuel containers which themselves are subjected to water pressure.

The use of such containers makes it possible for the performance of the propellant injection devices to be kept constant even without special regulators when pressure changes occur in the gas generator as a result of operating depth as the pressure acting on the propellant components is always equal to the ambient pressure which has to be overcome when the turbine exhaust gases are exhausted from the condenser.

The power absorbed by the propellant injection pumps thus hardly increases, if at all, when the pressure in the gas generator is increased with increasing depth. The pressure difference between the gas generator and the injection condenser and thus the expansion ratio determining the power supplied by the turbine are kept constant.

A further advantage is the saving in weight obtained by the use of thinner and lighter tank walls as the internal pressure is as great as the external pressure.

It has been found that salt residue from the evaporation of sea-water does not cause corrosion or mechanical damage to turbines.

The cooling and condensation of the exhaust gases by direct instead of indirect heat exchange with sea-water results in more compact and light weight heat exchangers and it is possible by selecting the quantity of sea-water to be injected per unit of time to regulate in a simple and more flexible manner the quantity of heat extracted from the exhaust gases to be cooled per unit of time.

In a preferred version of the driving system to which the invention relates, water is returned from the injection condenser to the sea-water injection device of the gas generator.

In a further preferred version of the invention the housing of the gas generator and/or that of the turbine are constructed and arranged so that the external walls are surrounded or swept by sea-water in contact with the surrounding sea as a result of which they are not only cooled but also constantly subjected on all sides to an external pressure so that the pressure strain is reduced when the internal pressure is varied in accordance with the depth of immersion in such a way that the expansion ratio remains constant.

One embodiment of the invention is described in conjunction with the accompanying drawing by way of an example.

The drawing shows schematically a drive system in accordance with the invention. The drive system includes tanks 1 and 2 which are internally subject to water pressure and containing fuel and oxidizing agent respectively, a gas generator 3, power turbine 4 and an injection condenser 5.

The tanks 1 and 2 contain flexible bladders la and 2a which can be subjected externally to ambient water pressure through pipes 6a, 6b fed with water from a main water pipe 6.

Fuel and oxidizing agent are withdrawn from the bladders la and 2a through pipes 7 and 8 respectively and injected into the gas generator 3 by means of a fuel pump 9 and a pump 10 for oxidizing agent via pipes 11 and 12 respectively. Water is injected into the hot propulsion gases occurring from the combustion of the propellant mixture in the gas generator 3. The water flows from the pipe 6 through a branch pipe 6c to a first water pump 13 and is fed from this through a first injection pipe 6d into the gas generator 3. The propulsion gases produced in the gas generator 3 mainly comprise steam and carbon dioxide which flow through a pipe 14 to the power turbine 4.The exhaust gas leaving the turbine 4 is fed through an exhaust-gas pipe 15 into the injection condenser 5 in which it is at least partly condensed by the injected sea-water fed via a branch pipe 6e, a second water pump 16 and a second injection pipe 6f. The condensate which forms in the condenser S is expelled together with the injected water and any un-condensed exhaust gas into the surrounding water through pipe 17.

The power turbine 4 drives through a shaft 18 and gear 19 the drive shaft 20 and pumps 9, 10, 13 and 16.

WHAT WE CLAIM IS: 1. A drive arrangement for underwater craft having a gas generator fed with a two component propellant from one tank containing liquid fuel and another tank containing liquid oxidizer, propellant gases acting on a single- or multi-stage power turbine, water being injected into the hot propellant gases before the turbine and the hot exhaust gas leaving the turbine passing to a cooler in which the exhaust gas is at least partly condensed before discharge

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. the exhaust gas is at least partly condensed before discharge externally of the craft, wherein the fuel and oxidizer are subject in use to ambient water pressure, the fuel comprising a hydrocarbon and/or an alcohol and the oxidizer comprising concentrated aqueous perchloric acid solution and/or hydroxyl ammonium perchlorate solution, and the cooler following the turbine comprising a condenser having means for the direct injection of cooling water. The design of the driving arrangement according to the invention using the foregoing combination of fuel and oxidizing agent, which is known as a high-energy and storable propellant for submarine drives but which because of the high combustion temperature and corrosive nature of the resulting propulsive gases was regarded as unsuitable for turbine drives, makes it possible to dispense with electrolytic sea-Rvater decomposition and gas liquefaction apparatus on board the vessel, to effect tank filling at any desired moment before actual use, and to dispense with costly insulation for the propellant tanks and propellant feed devices which are required when cryogenic propellants are used. It is also possible to use for the oxidizing agent and for the fuel containers which themselves are subjected to water pressure. The use of such containers makes it possible for the performance of the propellant injection devices to be kept constant even without special regulators when pressure changes occur in the gas generator as a result of operating depth as the pressure acting on the propellant components is always equal to the ambient pressure which has to be overcome when the turbine exhaust gases are exhausted from the condenser. The power absorbed by the propellant injection pumps thus hardly increases, if at all, when the pressure in the gas generator is increased with increasing depth. The pressure difference between the gas generator and the injection condenser and thus the expansion ratio determining the power supplied by the turbine are kept constant. A further advantage is the saving in weight obtained by the use of thinner and lighter tank walls as the internal pressure is as great as the external pressure. It has been found that salt residue from the evaporation of sea-water does not cause corrosion or mechanical damage to turbines. The cooling and condensation of the exhaust gases by direct instead of indirect heat exchange with sea-water results in more compact and light weight heat exchangers and it is possible by selecting the quantity of sea-water to be injected per unit of time to regulate in a simple and more flexible manner the quantity of heat extracted from the exhaust gases to be cooled per unit of time. In a preferred version of the driving system to which the invention relates, water is returned from the injection condenser to the sea-water injection device of the gas generator. In a further preferred version of the invention the housing of the gas generator and/or that of the turbine are constructed and arranged so that the external walls are surrounded or swept by sea-water in contact with the surrounding sea as a result of which they are not only cooled but also constantly subjected on all sides to an external pressure so that the pressure strain is reduced when the internal pressure is varied in accordance with the depth of immersion in such a way that the expansion ratio remains constant. One embodiment of the invention is described in conjunction with the accompanying drawing by way of an example. The drawing shows schematically a drive system in accordance with the invention. The drive system includes tanks 1 and 2 which are internally subject to water pressure and containing fuel and oxidizing agent respectively, a gas generator 3, power turbine 4 and an injection condenser 5. The tanks 1 and 2 contain flexible bladders la and 2a which can be subjected externally to ambient water pressure through pipes 6a, 6b fed with water from a main water pipe 6. Fuel and oxidizing agent are withdrawn from the bladders la and 2a through pipes 7 and 8 respectively and injected into the gas generator 3 by means of a fuel pump 9 and a pump 10 for oxidizing agent via pipes 11 and 12 respectively. Water is injected into the hot propulsion gases occurring from the combustion of the propellant mixture in the gas generator 3. The water flows from the pipe 6 through a branch pipe 6c to a first water pump 13 and is fed from this through a first injection pipe 6d into the gas generator 3. The propulsion gases produced in the gas generator 3 mainly comprise steam and carbon dioxide which flow through a pipe 14 to the power turbine 4.The exhaust gas leaving the turbine 4 is fed through an exhaust-gas pipe 15 into the injection condenser 5 in which it is at least partly condensed by the injected sea-water fed via a branch pipe 6e, a second water pump 16 and a second injection pipe 6f. The condensate which forms in the condenser S is expelled together with the injected water and any un-condensed exhaust gas into the surrounding water through pipe 17. The power turbine 4 drives through a shaft 18 and gear 19 the drive shaft 20 and pumps 9, 10, 13 and 16. WHAT WE CLAIM IS:

1. A drive arrangement for underwater craft having a gas generator fed with a two component propellant from one tank containing liquid fuel and another tank containing liquid oxidizer, propellant gases acting on a single- or multi-stage power turbine, water being injected into the hot propellant gases before the turbine and the hot exhaust gas leaving the turbine passing to a cooler in which the exhaust gas is at least partly condensed before discharge

externally of the craft, wherein the fuel and oxidizer are subject in use to ambient water pressure, the fuel comprising a hydrocarbon and/or an alcohol and the oxidizer comprising concentrated aqueous perchloric acid solution and/or hydroxyl ammonium perchlorate solution and the cooler following the turbine comes prising a condenser having means for the direct injection of cooling.

2. A drive arrangement according to claim 1 wherein water is returned from the condenser for injection into the propellant gases before the turbine.

3. A drive arrangement according to claim 1 or 2, wherein the gas generator and/or turbine are arranged to be in contact with external water.

4. A drive arrangement constructed and arranged to operate substantially as herein described with reference to the accompanying drawings.

5. A torpedo incorporating a drive arrange ment according to any preceding claim.