An indicator diagram is a chart used to measure the thermal, or cylinder, performance of reciprocating steam and internal combustion engines and compressors. The indicator diagram is used to calculate the work done and the power produced in an engine cylinder or used in a compressor cylinder.
Indicator diagrams are used to assess the performance of each unit of the ship's main engine. It is based on the indicator diagram that the overall performance of the engine is assessed. If there is any difference, it is important that the problem is rectified before starting the engine.
The indicator diagram (pv diagram or power card or work diagram), illustrates the pressure variations in the engine cylinder as a function of the main piston position. The diagram area can be integrated by means of a planimeter, and the mean indicated pressure calculated.
A curve showing variation of volume of a substance taken along the X-axis and the variation of pressure taken along Y-axis is called an indicator diagram or P-V diagram. The shape of the indicator diagram shall depend on the nature of the thermodynamical process the system undergoes.
The P-V diagram ( Indicator Diagram ) illustrates the variation of cylinder pressure; concerning the piston movement. The area of the diagram is calculated using a planimeter/platometer; and then multiplied by the cylinder constant and the engine speed.
– The area can be measured by an instrument known as 'Planimeter' or by the use of the mid ordinates rule. [On modern engines this diagram can be continuously taken by employing two transducers, one pressure transducer in the combustion space and other transducer on the shaft.
Effect of acceleration and friction on indicator diagram of reciprocating pump. As we have discussed in our previous post that the ideal indicator diagram of reciprocating pump will be basically a graph between the absolute pressure head in the cylinder and stroke length of the piston for one complete revolution.
Centrifugal Pump is a type of rotodynamic pump in which the flow through the pump is induced by the centrifugal force imparted to the liquid by rotation of the impeller.
Priming is done to put pump into working order by filling or charging with water. Why Priming is required ? Pressure developed by the impeller of centrifugal pump, is proportional to the density of the fluid in the impeller. If the impeller is running in air, it will produce only a negligible pressure.
Reciprocating Pump is a Positive Displacement type pump that works on the principle of movement of the piston in forwarding and backward directions whereas the Centrifugal pump uses the kinetic energy of the impeller to supply the liquid from one place to another place.
Slip is the internal back flow of fluid in a pump returning from the discharge side to the suction side. Displacement pumps, on the other hand, rely on the pumped fluid for lubrication and a certain amount of back flow and slippage is necessary to ensure smooth operation.
Major places where cavitation occurs are in pumps, on propellers, or at restrictions in a flowing liquid. As an impeller's (in a pump) or propeller's (as in the case of a ship or submarine) blades move through a fluid, low-pressure areas are formed as the fluid accelerates around and moves past the blades.
There are three types of mechanism defined reciprocating pumps: piston, plunger and diaphragm or bellows. Valves at each end of the volume alternately close and open to isolate the higher pressure volume from the suction on the compression stroke and the higher pressure discharge from the volume on the return stroke.
Cavitation happens when bubbles, or voids, form within a fluid because the pressure quickly drops below the vapor pressure. When the bubbles experience higher pressures they collapse, creating small shockwaves that, over time, damage parts. When these pressure waves punch tiny holes into parts, it's called pitting.
These pumps have the unique ability to produce higher and higher pressures with the addition of every stage, but flow range always remains constant for a given rpm. Thus, Multistage are series connection hence discharge remains constant while the head increases.
engineering. : a numerical coefficient by which the area of an ideal indicator diagram or its mean effective pressure must be multiplied to approximate that of the probable actual indicator diagram or the probable actual mean effective pressure.
Definition of Richards's indicator: a steam-engine indicator using a straight-line reducing motion between the working piston and the recording stylus or pencil which makes it suitable for use on high-speed engines.
marine. The power developed in an engine cylinder. It is determined from an indicator diagram and certain basic information about the engine.
Compression is a schematic layout algorithm that is typically used on diagrams with containers so the features in the containers are processed as junction groups. This layout algorithm compresses the diagram features toward the middle of the diagram while trying to maintain relative positioning.
Steam engine works on the principle of first law of thermodynamics where work and heat are mutually convertible. This is a very basic defination of steam engine. In a steam engine there is a cylinder fitted with a piston.
The cylinder is the space through which the piston travels, propelled to the energy generated from the combustion of the air/fuel mixture in the combustion chamber. In an air-cooled engine, the walls of the cylinders are exposed to the airflow, to provide the primary method of cooling to the engine.
In various contexts of science, technology, and manufacturing (such as machining, fabricating, and additive manufacturing), an indicator is any of various instruments used to accurately measure small distances and angles, and amplify them to make them more obvious.
