The BLADES ON THE IMPELLER GATHER BUBBLES AND POP. THE POP OF THE BUBBLES BREAK AND INDENT THE IMPELLER AND GUIDEVANE THAT HELPS THE WATER OR FLUID GO FROM THE MIDDLE OF THE IMPELLER TO THE LEADING EDGE OF THE IMPELLER. THE SOUND OF CAVITATION IS LIKE PUMPING GRAVEL THROUGH THE VOLUTE OR CASE. IF THE PUMP IS CAVITATING YOU CAN SLOWING CLOSE A BALL VALVE ON THE DISCHARGE SIDE OF THE PUMP ON A CENTRIFUGAL PUMP AND THE GRAVEL NOISE WILL GO AWAY AND YOU KNOW THE PUMP IS CAVITATING. CAVATION WILL DESTROY AN IMPELLER VERY FAST BY IMPLODING BUBBLES ON THE METAL OR PLASTIC UNTILL THE PUMP WILL NOT RUN.
the propeller shaft in the after peak tank is provided with inboard and outboard seals.these seals contain nitrile rubber or viton lip seal which seals against the bronze liner shrunk fit around the cast iron propeller shaft.after a few years it creates grooves on them and naturally looses sealing and sea water can easily find its way inside.this reduces the lubrication effect and creates wear if the bronze liner.now as there is enough clearance the shaft will come down by certain amount because of the propeller weight.this drop in propeller shaft is termed as propeller drop and is measured by POKERS gauge.
Fans can have any number blades--even one! (but then you need a counterweight for balance). There are airplanes that have one blade for a propeller. There are many variables that figure into how many blades a fan has. Air velocity, noise, shape of the blade, length of the blade, material cost, vibration, etc. For airplanes sometimes they change 2-bladed propellers for three or four or more to get different flying characteristics.
What is meant by resonance and explain the series and parallel resonance? by kathiresan
A: The pitch angle is a speed factor and also a torque factor. Increasing or decreasing the angle will effect these factors inversely
aries.ucsd.edu/NAJMABADI/CLASS/ECE65/06-W/NOTES/BJT3.pdf
Cavitation is an effect. It is caused by gas bubbles forming in water adjacent to a fast moving propeller blade.
ignition safety switch lanyard ETA: AKA: the "Kill Switch". Better than that is a good competent knowledge of boat handling and situational awareness. ---------------------------------------------------------------------------------------------------------- While the above may kill the engine if the driver falls overboard, it would have no effect for when the driver runs over a person or an animal in the water. To prevent propeller injury , the propeller needs to be encased in a shroud or guard so that large objects can not be drawn into the blades. In my view all pleasure craft with exposed propellers should be fitted with these but people do not do so because it increases drag.
ignition safety switch lanyard ETA: AKA: the "Kill Switch". Better than that is a good competent knowledge of boat handling and situational awareness. ---------------------------------------------------------------------------------------------------------- While the above may kill the engine if the driver falls overboard, it would have no effect for when the driver runs over a person or an animal in the water. To prevent propeller injury , the propeller needs to be encased in a shroud or guard so that large objects can not be drawn into the blades. In my view all pleasure craft with exposed propellers should be fitted with these but people do not do so because it increases drag.
ignition safety switch lanyard ETA: AKA: the "Kill Switch". Better than that is a good competent knowledge of boat handling and situational awareness. ---------------------------------------------------------------------------------------------------------- While the above may kill the engine if the driver falls overboard, it would have no effect for when the driver runs over a person or an animal in the water. To prevent propeller injury , the propeller needs to be encased in a shroud or guard so that large objects can not be drawn into the blades. In my view all pleasure craft with exposed propellers should be fitted with these but people do not do so because it increases drag.
ignition safety switch lanyard ETA: AKA: the "Kill Switch". Better than that is a good competent knowledge of boat handling and situational awareness. ---------------------------------------------------------------------------------------------------------- While the above may kill the engine if the driver falls overboard, it would have no effect for when the driver runs over a person or an animal in the water. To prevent propeller injury , the propeller needs to be encased in a shroud or guard so that large objects can not be drawn into the blades. In my view all pleasure craft with exposed propellers should be fitted with these but people do not do so because it increases drag.
A propeller on a submarine (which is called a screw, by the way) works to convert the rotational energy of the shaft into propulsion. The screw is a hydrofoil with blades attached to a heavy central hub or boss. The blades are inclined to the plane of rotation. For forward motion, the screw rotates in a given direction, and the leading edge of the screw "bites" into the water ahead of the plane of rotation. This has the effect of pushing water backwards. The rest of the blade follows along and continues to push the water backward. When water is forced back, the submarine is forced forward, and this is a play out of the action-reaction chapter in a physics book. A link can be found below for more information, and you can see a diagram or two, which will help greatly.
Their tail-rotors counter-act the torque (or spinning) effect of the overhead propellors
Efficiency is reduced because the propeller exerts less force at high density altitudes than at low density altitudes. Less efficient slow plane
Explain the effect of molecular polarity on behaviour.
dont know the answer
Rotation, no. Lift, yes. If you increase the surface area of the propeller, then you alter the lift to weight ratio.
the propeller shaft in the after peak tank is provided with inboard and outboard seals.these seals contain nitrile rubber or viton lip seal which seals against the bronze liner shrunk fit around the cast iron propeller shaft.after a few years it creates grooves on them and naturally looses sealing and sea water can easily find its way inside.this reduces the lubrication effect and creates wear if the bronze liner.now as there is enough clearance the shaft will come down by certain amount because of the propeller weight.this drop in propeller shaft is termed as propeller drop and is measured by POKERS gauge.