What is motive fuel flow?
What is motive fuel flow?
Motive flow is required in design of ejector pumps in fuel system. When the high pressure motive flow passes through the throat it creates a suction which sucks fuel from its neighborhood and the total fuel flow are sent to another location.
What is motive fluid?
A high-pressure fluid used to produce flow of another fluid, as in an ejector. Access to the complete content on Oxford Reference requires a subscription or purchase.
Where does the motive fluid enter the ejector?
Ejector Operation: In operation, a high-pressure motive gas enters the steam chest at low velocity and expands through the converging-diverging nozzle. This results in a decrease in pressure and an increase in velocity. Meanwhile, the suction fluid enters at the suction inlet.
How does an ejector fuel pump work?
Ejector pumps are the pumps that use motive fluids to pump the fluids. Motive fluids are the fluids in motion. The fluid that is to be pumped is called as the suction fluid. These pumps work on the venturi effect using a converging-diverging nozzle and pump the fluid.
What type of fuel booster pump requires a pressure relief valve?
aircraft centrifugal fuel boost pump
How does a rotary vane fuel pump work?
Vanes are allowed to slide into and out of the rotor and seal on all edges, creating vane chambers that do the pumping work. On the discharge side of the pump, the vane chambers are decreasing in volume, forcing fluid out of the pump. The action of the vane drives out the same volume of fluid with each rotation.
What are the two types of vane pumps?
There are two types of vane pumps: 1. Unbalanced vane pump: Unbalanced vane pumps are of two varieties: Unbalanced vane pump with fixed delivery.
How many valves are required for the rotary pump?
Explanation: There are no valves required for a rotary pump. A rotary pump is the one in which the flow is continuous. Since, the flow is continuous, we do not require any valves. 2.
What is a balanced vane pump?
Balanced Vane Pumps. In the balanced design (Figure 3-10), a pump has a stationary, elliptical cam ring and two sets of internal ports. A pumping chamber is formed between any two vanes twice in each revolution. The two inlets and outlets are 180 degrees apart.
What controls the direction of the flow of oil?
Directional control valves (DCVs) are one of the most fundamental parts of hydraulic and pneumatic systems. DCVs allow fluid flow (hydraulic oil, water or air) into different paths from one or more sources.
What is the difference between vane pump and radial piston pump?
Hydraulic vane pumps are used in die casting, injection moulding machines industry plus land and road construction machinery. Piston pumps handle large flows at high hydraulic system pressures delivering optimum efficiency and reliability while maintaining a compact size with a high power density.
How does the fluid flow in internal gear pump?
An internal gear pump moves a fluid by repeatedly enclosing a fixed volume within interlocking gears, transferring it mechanically to deliver a smooth pulse-free flow proportional to the rotational speed of its gears.
Can you run a gear pump in reverse?
It Flows Both Ways: A guide to running an internal gear pump in reverse. One of the biggest limitations of a traditional centrifugal pump is its inability to reverse the direction of flow. By design it can only be run in one rotation and one direction of flow.
Do gear pumps need to be primed?
Gear Pumps are self-priming, ie, they require no priming, which is one of the major advantages of these pumps. Besides they also have a high volumetric efficiency and constant delivery at a given speed.
Can a gear pump be used as a motor?
Pumps and motors are designed differently so they are not completely interchangable. In fact, only gear pumps can be used as hydraulic motors. Piston and vane pumps will not work as a hydraulic motor at all. So there are really two instances where you would want to use a hydraulic motor as a pump.
What is the function of flow control valve?
The purpose of a flow control valve is to regulate the flow rate in a specific portion of a hydraulic circuit. In hydraulic systems, they’re used to control the flow rate to motors and cylinders, thereby regulating the speed of those components.
What is difference between hydraulic motor and pump?
While a hydraulic pump is connected to a prime mover, with the pump shaft with no extra radial load, the hydraulic motor is connected to the load via pulleys, sprockets and gears, so its main shaft can bear an increased radial load. A hydraulic pump typically has a vacuum in its low pressure chamber.
How do I increase the pressure on my gear pump?
Some fluid will seep through the gap between the sides of the gears and the endplates (see figure below.) This gap must be small in order to maintain the pressure increase across the pump. Increasing the gap diminishes the pumps ability to hold a pressure difference between the inlet and outlet.
What is the difference between internal and external gear pump?
An external gear pump consists of two identical, interlocking gears supported by separate shafts. An internal gear pump has two interlocking gears of different sizes with one rotating inside the other. Gear pumps are commonly used for pumping high viscosity fluids such as oil, paints, resins or foodstuffs.
How does an internal gear pump prevent the fluid from flowing through the motor?
The fluid is carried by the gears to the discharge side of the pump, where the meshing of the gears displaces the fluid. The mechanical clearances are small— in the order of 10 μm. The tight clearances, along with the speed of rotation, effectively prevent the fluid from leaking backwards.
What is squeezing in gear pump?
Gear pump Design Gear pumps use toothed gears turning inside a close tolerance housing to draw-in liquid and then squeezing it out ahead of them. Paddle steamers used the same principle of operation. These pumps are positive displacement pumps and anything drawn into them will be forced out.
Can gear pump be used for water?
The gear water pump is a popular choice for many applications. They aren’t always used for water, though. They are used in the petrochemical and chemical industries and make great pumps for hydraulic applications. They can be used for viscous and aggressive fluids.
What pump is known as positive displacement pump?
Positive displacement pumps are also advantageouses known as a PD pump, it is an umbrella term for a pump type that does not have impellers like a centrifugal pump. A positive displacement pump uses a variety of rotating or reciprocating parts to move fluid into an enclosed volume.
What are the main components of a gear pump?
External gear pumps consist of these main components:
- Driving gear.
- Driven (idler) gear.
- Pump housing.
- End plates.
- Side plates.
Why external gear pump produce the noise?
The causes of noise generation are as follows [6]: (1) Pressure shock and cavitation arising from the trapped volume between meshing teeth; (2) the noise caused by some manufacturing errors of gears during gear meshing; (3) flow pulsation and pressure pulsation caused by the volume change of the suction chamber and …
How do you calculate the flow rate of a gear pump?
- Formula to calculate gear pump displacement.
- Q = π x b x (da.
- 2 – a2.
- )
- Q = Displacement cm.
- /rev. b = Gear Width cm. ( see photo 1) da = Gear tip diameter cm. ( see photo 2)
- P. Photo 1 – shows gear width 1.614cm. Photo 2 – shows tip diameter 5.039cm Photo 3 – shows gear centres 4
What is advantage of internal gear pump?
The advantages of an internal rotary gear pump – Smooth flow of viscous fluids. Although the pump does handle solids and abrasive material well, the pump can handle shear sensitive fluids with a gentle non-pulsating flow thanks to the cumulative, smooth delivery of the gear teeth meshing.
What is the pressure range of internal gear pump?
The QXV unit is an internal gear pump for low−viscosity fluids. By using several pump stages connected in series, pressures to 250 bar can be developed with high efficiency at viscosities of around 1 mm2/s .
How is pressure created in a flow system?
First, its mechanical action creates a vacuum at the pump inlet which allows atmospheric pressure to force liquid from the reservoir into the inlet line to the pump. It produces the flow necessary for the development of pressure which is a function of resistance to fluid flow in the system.
What causes internal leakage in internal gear pump?
(b) Internal structure of pump. Hydraulic oil is transported from inlet to outlet as the driving gear rotates. The leakage is caused by the clearance h1 and h2 when the gear pumps are operational, as shown in Figure 2.