Subyek: WATERJET PROPULSION. Sun May 23, 2010 9:05 am
Overview. Waterjets are now accepted as a proven technology, particularly for high speed craft and they are increasing their penetration into small craft, leisure, workboat, patrol and military markets. Today, waterjets are becoming the preferred propulsion choice where high efficiency, enhanced manoeuvrability, shallow draft capability and low maintenance are key requirements. Continuing developments now include very large units of 30MW capacity and the use of waterjets for high speed boost propulsion.Hamilton Jet
As the technology matures, designers need better tools to help predict the performance and efficiency of these systems across a wide range of operating conditions. Computational fluid dynamics is an increasingly powerful tool which has become almost universal, but traditional model testing and trials measurements are still required to confirm critical results.
Designers and manufacturers also continue to seek to reduce noise, wake and wash as well as optimise the strength and weight of the various mechanical components and to improve reliability, reduce installation time and maintenance.
A pump-jet or water jet is a marine system that creates a jet of water for propulsion. The mechanical arrangement may be a ducted propeller with nozzle, or a centrifugal pump and nozzle.
Pump jets have some advantages over bare propellers for certain applications, usually related to requirements for high-speed or shallow-draft operations. These include:
* Increasing the speed for the onset of cavitation, due to the raised internal dynamic pressure * High power density (with respect to volume) of both the propulsor and the prime mover (since a smaller, higher-speed unit can be used) * Protection of the rotating element and making operation safer around swimmers * Improved shallow-water operations, since only the inlet needs to be submerged * Increased maneuverability, by adding a steerable nozzle to create vectored thrust * Ultra-quiet designs for submarines; for example the the Royal Navy Trafalgar-class, the US Navy Seawolf-class, and the French Navy Le Triomphant class * Propulsion of torpedoes; for example the Spearfish or Mark 48
In these situations, the benefits outweigh the somewhat reduced efficiency (especially marked at low forward speeds) caused by the increased wetted surface and higher rotational speeds than an open propeller. One disadvantage is that pump jets (especially when fitted to outboard engines) are prone to becoming clogged with debris such as seaweed. The operator must clear the impeller by stopping the craft and briefly revving the engine in reverse.
CODAG WARP (Combined Diesel and Gas - Water Jet and Refined Propeller) propulsion system of the A-200 SAN.
* Computer generated image of the Meko Class A-200 frigate * Valour Class (Meko A-200) armed with Exocet anti-ship missiles * Outline drawing of the Meko A-200 SAN showing arrangement of weapons and systems * Drawing of the MEKO A Class Corvette propulsion system * Face on view of the Meko A class Corvette * Royal Malaysian Navy built Kedah Class (Meko A-100) patrol vessel * MEKO 140 Espora Class Corvette of the Argentine Navy side profile * Rear view of the Meko Class combat ship with helicopter on deck * Turkish frigate Barbaros a modified MEKO 200-type vessel
Outline drawing of the Meko A-200 SAN showing arrangement of weapons and systems . WATERJET FOR FRIGATE.
WATERJET PROPULSION SYSTEM BISA DI TERAPKAN PADA TORPEDO, ASSAULT AMPHIBIOUS VEHICLE, LEISURE WATER CRAFT, LCU, FREGATE, KAPAL SELAM DLL HANDAL DI PERAIRAN DANGKAL.
Sun May 23, 2010 9:05 am
