Turbines rotate due to force exerted by one or more water jets that are directed tangentially onto the turbine’s vanes or buckets. The impact of the water on the vanes
generates a torque on the wheel
, causing it to rotate and to generate electricity.
What is impact of jet in fluid mechanics?
4.2 Impact of jet
A jet is
a stream of fluid that is projected into a surrounding medium
, usually from some kind of a nozzle, aperture or orifice. [1] Jets can travel long distances without dissipating. Jet fluid has higher momentum compared to the surrounding fluid medium.
What is meant by impact of jet on Vane?
When the jet of water strikes on the obstruction like a flat. inclined, hemispherical plate vanes in its path, then
the jet
.
exerts the force on the obstruction
is known as Impact of. jet.[1] Newton second law of motion states that “the. applied force is equal to rate of change in momentum.” [
When water jet strikes on a number of flat plates mounted on the periphery of a wheel the the maximum efficiency of the wheel will be?
Show that the efficiency of jet can never exceed
50%
. Hence prove that the efficiency of a free jet striking normally on a series of flat plates mounted on the periphery of a wheel can never exceed 50%.
What is the work done by the jet on the plate when the plate is stationary?
Explanation: In a stationery vertical plate, the jet after striking the plate will move along the plate. It moves with respect to the angles that are developed with the plate. Hence, after striking the
plate it will get deflected at an angle of 90 degrees
.
What is meant by impact of jet?
Thus impact of jet means
the force exerted by the jet on a plate which may be stationary or moving
. In this chapter, the following cases of the impact jet i.e., the force exerted by the jet on a plate, will be considered: Force exerted by a jet on a stationary plate when.
What is the application of impact of jet?
2 Introduction. One of the applications of jet impact is
used to generate electricity
. Impact of jet is used to rotate the turbine namely Pelton wheel in the generator. The water jet is applying force tangential to the wheel.
How do you calculate the force of a water jet?
If the speed of the water jet is constant (ie. dv/dt=0), the force is given by
f = v(dm/dt)
where v is the speed of the water exiting the nozzle and dm/dt is the mass flow rate out of the nozzle. The mass flow rate is the volume flow rate x mass/unit volume of water (1 kg/l).
What is the impact of jet and jet propulsion?
Jet propulsion is
the propulsion of an object in one direction, produced by ejecting a jet of fluid in the opposite direction
. By Newton’s third law, the moving body is propelled in the opposite direction to the jet.
How is jet Reaction calculated?
The nozzle reaction is found to be:
R = ρ Q
2
/ A
2
, where A
2
is the discharge diameter, Q is the volumetric flow rate, R is the magnitude of the nozzle reaction, and r is the water density. This equation shows that the reaction is proportional to the flow rate squared, divided by the nozzle diameter.
What is maximum efficiency when jet strike on a series of a flat plate *?
A free jet striking normally on a series of flat plates mounted on the periphery of a wheel. that the efficiency of jet doesnt exceed
50%
. Hence prove that the efficiency of a free jet striking normally on a series of flat plates mounted on the periphery of a wheel can never exceed 50%.
What is the formula for forces exerted by fluid on a body?
The body force per unit mass at a point x in the fluid at time t is F(x,t). The total force on an infinitesimal element of volume δV is then
F(x,t)ρδV
. For gravity, F(x,t) = g making the total gravitational force equal to ρgδV .
What is maximum efficiency for semi circular vanes *?
In case of semi-circular vanes, thb theoretical maximum efficiency of the wheel can be.
50%
When a jet strikes an inclined plate?
When a jet strikes an inclined fixed plate, as in Fig. P3. 46, it
breaks into two jets at
2 and 3 of equal velocity V = Vjet but unequal fluxes αQ at 2 and (1 – α)Q at section 3, α being a fraction. The reason is that for frictionless flow the fluid can exert no tangential force Ft on the plate.
Which among the following is the formula for force when jet strikes the stationary plate?
Explanation: When a force can be resolved into two components, one in the direction of the jet and the other perpendicular to the jet. The formula for force when it acts perpendicular to the direction of flow is equal to
pav
2
SinθCosθ
.
How is absolute velocity at inlet tip is denoted?
How is absolute velocity at inlet denoted? Explanation: In a jet propulsion,
V
1
stands for absolute velocity at the inlet. The main application in which this equation is applied is for a jet propulsion in the tank with orifice. Thus, the correct option is ‘b’.
