Archive for September 2011

Working model of Hovercraft

September 29, 2011

The idea of making a Hovercraft dates back to 1716 when Emmanual Swedenborg recorded a design, but it was short lived.  In 1870, Sir John Thornycroft filled patents involving air lubricated hulls. And it was in 1959 a hovercraft was built, by Christopher Sydney Cockerell  by discovering the Momentum Curtain theory. Hover craft also called Air cushion vehicle (ACV) travels on any kind of flat surface. It is supported by a cushion of pressurized air.

Design

  • Can be powered by one or more engines
  • Small crafts have a single engine with the drive split through a gear box
  • Usually one engine drives the fan responsible for lifting the vehicle
  • The other forces air from

hovercraft

Working

Two main principles:

1)      Lift

2)      Propulsion

  • A skirt is required to quarantine airflow
  • No contact with ground hence friction is eliminated
  • The shape of the body affects stability
  • All parts are essential for proper working

Parts

1)      Lifting fan: Usually a centrifugal fan is preferred. When rotated air is sucked into the center hole, it is coupled via a gearbox and connected to the engine

2)      Thrust propellers: An aircraft type propeller with variable type pitch blades. Diameter ranges from nine feet to nineteen feet. In bigger crafts the propellers are rotated while in smaller ones, rudders are used.

3)      Skirt: Flexible strip which is fitted below the bottom edges of the plenum chamber. Skirt design is the most sensitive design parameter as it protects the craft and helps to lift it even higher.

hovercraft diagram

In theory hover crafts are simple machines but a plethora of problems exist to make a functioning hovercraft. The plans as well as the design must be flawless. To build a hovercraft one must be well aware of the demands of construction. Only then can one design a hovercraft.

Pneumatic paper cup forming machine

September 29, 2011

Pneumatic paper cup forming machine” is a wonderful project topic for mechanical engineering students.

In a pneumatic system, energy is stored in a potential state in the form of compressed air. Working energy is produced in a pneumatic system when the compressed air is allowed to expand. So, in order to do work, a device is required which is able to supply an air tank with sufficient amount of air at a desired pressure. This device usually happens to be a positive displacement compressor.

Advantages of using a pneumatic machine:

1)    Lower cost than Hydraulic Machines

2)    Works on air which is freely available.

3)    Compact when compared with Hydraulic Machines

4)    Energy can be controlled relatively easily using valves.

 

The procedure for the development of the paper cup has been broken down into 5 stages

Stages of development:

1)      Body Sealing

A Cup fan wall shaped sheet of paper should be first sealed so as to obtain a cone shape.

2)      Bottom inserting

Round pieces which serve as the bottom of the cup is inserted into the cone and sealed

3)      Bottom knurling

Knurling of the excess portion of the cone is done

4)      Rim Curling

Rim curling is done to make the cup end curled.

5)      Dispensing

The finished cups are automatically discharged from machine.

Pneumatic paper cup forming stages

Factors to be taken into account while designing the cup:

1)      Bottom diameter

2)      Top diameter

3)      Height

4)      Bottom knurling height

5)      Side sealing width

Note:

For best results double PE coated paper is used in the development of cups. Since, in one side PU coated paper cups the paper becomes softened and the chances for the beverage to leak out are high.

Electrical Power Generation System Using Railway Track

September 29, 2011

The system includes a power source, such as a power generation device or an external powersource. The power co-generation system includes first and second electrical capacitance portions that are electrically coupled to the power source and that are configured to carry positive and negative charges, respectively. The power co-generation system further includes a biasing device that is configured to separate the first and second capacitance portions with respect to one another. Thus, by varying the distance between the capacitance portions in response to a vehicle on the rail, the capacitance portions cooperate to act as a variable capacitor that facilitates the co-generation of power with respect to the system. That is to say, the mechanical energy of the biasing device is converted into electrical energy for the system.

 

In accordance with another exemplary aspect of the present technique, a method of co-generating power via a vehicle traveling on a rail is provided. The method includes the act of driving first and second capacitor plates with respect to oneanother in response to the vehicle that is traveling on the rail. The method also includes the act of charging the first and second capacitor plates via a power source, such as a power generation device or an external power source. The method  further includes biasing the first and second plates apart from one another, thereby displacing the plates with respect to one another. This displacement changes the electrical capacitance between the first and second plates and, resultantly, increases the electric potential between the first and second plates. In turn, this displacement of the first and second plates facilitates the co-generation of electrical energy from the kinetic and potential energy of the vehicle on the rail.

Reference

Hydrogen (water) Powered vehicle

September 29, 2011

Not a Gimmick! Finally the science of Hydrogen automotive power has been made a reality! Technically a device that converts the energy stored in hydrogen into motion can be called a Hydrogen engine. Hydrogen would make a great fuel for the environment since burning Hydrogen produces nothing but water!

Hydrogen Powered vehicle essentially consists of the following

1)      Fuel tank

Liquid hydrogen is stored in a tank at the rear of the car and is pumped forward to the fuel cell stack as and when required.

2)      Fuel Cell Stack

When Hydrogen is combined with Oxygen in a fuel cell a chemical reaction creates electricity.

Hydrogen Powered vehicle

 

1)      Battery Pack

The battery pack is periodically recharged by the fuel cell. The power from the battery pack is used to provide rapid acceleration.

2)      Electric Motor

The stack provides electricity for the electric motor that powers the vehicle

Right from the year 1625, when Johann Baptista van Helmont discovered the gas, Hydrogen; people were curious enough to find the uses of the new found gas. It nearly took a mind boggling 181 years to develop an internal combustion engine which runs on a mixture of hydrogen and water by the icon of 18th century who is none other than, Francois Issac de Rivaz. The Swiss inventor, is credited with the development and construction of the world’s first IC engine back in 1806. From then onwards, it was always a challenge to develop the best IC engine. This has lead to developing different varieties of engines.

A pictorial representation of the Hydrogen powered vehicle is shown below.

Hydrogen Powered vehicle