Posts Tagged ‘crankshaft’

A Look Inside a Reciprocating Steam Engine

Wednesday, December 6th, 2017

    Last time we developed an engineering formula to calculate the horsepower required to accelerate a flywheel by way of a reciprocating steam engine, which contributes to the storage of kinetic energy inside a flywheel.   Today we’ll gain a clearer understanding of how this works when we take a look inside a reciprocating steam engine.

A Look Inside a Reciprocating Steam Engine

A Look Inside a Reciprocating Steam Engine

   

    A reciprocating steam engine performs the work of transforming steam’s heat energy into the mechanical energy needed to move a piston contained within a cylinder.   During a complete operating cycle this piston travels from one end of the cylinder to the other, then back again.   This is made possible because during the first half of the cycle pressurized steam enters one end of the cylinder and expands inside it, forcing the piston to move.

    This process inside the cylinder results in movement of a piston that’s attached to a piston rod, which in turn is connected to a crankshaft via a connecting rod and crank rod.   The crankshaft is a device which converts the reciprocating linear motion of an engine’s piston into rotary motion and in so doing facilitates the powering of any externally mounted rotating machinery attached to it.   So long as there’s ample steam to power the internal piston, over time, energy in the form of horsepower will be available to externally mounted devices.   The energy in the steam decreases as the steam expands behind the moving piston. So, the engine’s horsepower, will decrease as the piston travels to the end of the cylinder.   If the energy in the steam should become depleted, the reciprocating steam engine will stall. The engine will no longer be able to perform work.

    Next time we’ll see how a crankshaft works when we take a look inside it.

opyright 2017 – Philip J. O’Keefe, PE

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