What is the function of the guide vanes in Francis turbine?
What is the function of the guide vanes in Francis turbine?
Guide and stay vanes: The primary function of the guide and stay vanes is to convert the pressure energy of the fluid into kinetic energy. It also serves to direct the flow at design angles to the runner blades. Runner blades: Runner blades are the heart of any turbine.
What is an outlet guide vane?
The outlet guide vane (OGV) has two different purposes: Forming a structural connection between the main engine carcass and the aircraft attachment point. Steering the flow coming from the low-pressure turbine into the axial outflow, i.e. an aerodynamic objective.
Do inlet guide vanes rotate?
Inlet guide vanes impart a whirling motion to the inlet airflow in the same rotational direction as the impeller. This decreases the power required to deliver the rated airflow and pressure. There are opportunities for energy savings when the compressor inlet is throttled.
What do guide vanes do?
Guide Vanes are fixed grooves found in turbines that help direct water, gas, or air around bends at maximum efficiency. As Impellers increase or decrease the flow of a substance through a system, Guide Vanes ensure that the substance is passed evenly and as smoothly as possible.
Which turbine have adjustable guide vanes?
Kaplan turbines
There are variants of Kaplan turbines that only have adjustable inlet guide-vanes or adjustable rotor blades, which are known as semi-Kaplan’s.
What are the functions of guide vane runner and draft tube in Francis turbine?
Abstract. The draft tube is an important component of a Francis turbine which influences the hydraulic performance. It is located just under the runner and allowed to decelerate the flow velocity exiting the runner, thereby converting the excess of kinetic energy into static pressure.
What are the different types of vanes?
They include the conventional axial, mixed flow and radial vane forms; however, a differentiation between different flow directions (i.e. from the inside to the outside or vice versa) is not made.
What is the difference between a blade and a vane?
Blades must operate at high rotating speeds and temperatures, while vanes direct the stream propelled by the rotating blades to the next turbine stage with optimum efficiency. Both blades and vanes must be resistant to oxidation, corrosion and wear, and provide longevity in service.
What is inlet guide vanes?
Inlet guide vanes may be either fixed or variable. They are usually located ahead of each impeller eye (Fig. 8.31) and are designed to guide the flow of gas efficiently into the eye of the impeller. Most process compressors use fixed since most vanes usually corrode/foul and jam.
What are variable guide vanes?
Abstract. The variable guide vanes (VGV) of gas turbine engines are commonly utilized to expand operating range and to improve efficiency of the compressor. Guiding air flow using the VGVs in the compressor prevents aerodynamic instability by making proper incidence angle to the blades.
What is nozzle guide vanes?
Nozzle guide vanes (NGVs) are static components mounted into the casings of gas turbine engines as e.g. aircraft turbines. Typically, nozzle guide vanes are designed to convert part of the gas flow’s heat and pressure energy into a tailored kinetic energy from which rotor blades can generate power.
What are the stationary guide vanes fixed on?
The stationary guide vanes are fixed on the guide mechanism. The guide vanes allow the water to strike the vanes fixed on the runner without shock at the inlet. The guide vanes ( also called as wicket gates) are fixed between two rings. This arrangement is in the form of a wheel and called a guide wheel.
How do you adjust the opening between the vanes?
The opening between the vanes can be increased or decreased by adjusting the guide wheel. The guide wheel is adjusted by the regulating shaft which is operated by a governor. The guide blades rest on pivoted on a ring and can be rotated by the rotation of the ring, whose movement is controlled by the governor.
What is the purpose of inlet guide vanes?
They are used to change the slope of the compressor performance curve. The effect of inlet guide vanes is shown in Fig. 8.33.
What are nozzle guide vanes?
Typical nozzle guide vanes showing their shape and location. (Source: Rolls Royce.) The nozzle guide vanes are usually of hollow form and may be cooled by passing compressor delivery air through them to reduce the effects of high thermal stresses and gas loads.
