Fluid Mechanics

Hydraulic Machines

Hydraulic Machines are the machines which convert either hydraulic energy into mechanical energy or mechanical energy into hydraulic energy. The machines whic convert the hydraulic energy into mechanical energy are called turbines while the hydaulic machines which convert the mechanical energy into hydraulic energy are called pumps.

Classification of Hydraulic Turbines 

According to the type of energy at inlet:

1. Impulse Turbine

2. Reaction Turbine

According to the direction of flow through runner:

1. Tangential flow turbine

2. Radial flow turbine

3. Axial flow turbine

4. Mixed flow turbine

According to the head:

1. High head turbines

2. Low head turbines

3. Medium head turbines

Pelton Tubine

Pelton turbine is a tangential flow reaction turbine. The flow of water enters into the turbine along the tangent of the runner. The energy available at the inlet of the turbine is Kinetic energy. The pressure available at inlet and outlet will be atmospheric pressure. This turbine is used for producing high head of water. The water from the reservoir flows through the penstocks at the outlet of which a nozzle is fitted. The nozzle increases the kinetic energy of the water flowing through the penstock. At the outlet of the nozzle,  the water comes out in the form of a jet and strikes the buckets of the runner. The main part of the pelton turbine are;
1.Nozzle and flow regulating arrangement
2.Runners and buckets
3.Casing
4.Breaking jet

Gating system

Gating System

The process which involves pouring of molten metal into a long, which is a cavity formed in some minding material such as sand. The mold cavity exactly assembles in shape and size with the product to be made by casting. The molten metal, poured into the mold and allowed to freeze there, takes up the shape of the mold cavity and the product this cast, is called a casting.

The gating system is also called Sand molding. Essential features of sand mold are:

1. Pouring Cup: Pouring Cup is an enlarged cup shapes cavity made at the top of vertical sprue to help easy feeding of molten metal into the mold from the paddle.
2. Runner: Runners are the channels to carry molten metal from the sprue to the mold cavity.
3. Core: Core is the insert placed in the mold cavity to form hollow regions within the casting.
4. Drag: Drag is the part of the molding sand which holds molten metal upward.
5. Riser: Riser are specially designed to keep the metal in them inmolten state until the casting is fully solidified.