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The joule (/ dʒ uː l / JOOL, or / dʒ aʊ l / JOWL; symbol: J) is the unit of energy in the International System of Units (SI). [1] In terms of SI base units , one joule corresponds to one kilogram - square metre per square second (1 J = 1 kg⋅m 2 ⋅s −2 ).
This usage is also followed by Glansdorff and Prigogine in their 1971 text about continuous-flow systems. They write: "Again the flow of internal energy may be split into a convection flow ρuv and a conduction flow. This conduction flow is by definition the heat flow W. Therefore: j[U] = ρuv + W where u denotes the [internal] energy per unit ...
A simplified version of the definition is: The k v factor of a valve indicates "The water flow in m 3 /h, at a pressure drop across the valve of 1 kgf/cm 2 when the valve is completely open. The complete definition also says that the flow medium must have a density of 1000 kg/m 3 and a kinematic viscosity of 10 −6 m 2 /s, e.g. water. [clarify]
Joule immersed a length of wire in a fixed mass of water and measured the temperature rise due to a known current flowing through the wire for a 30 minute period. By varying the current and the length of the wire he deduced that the heat produced was proportional to the square of the current multiplied by the electrical resistance of the ...
Between 1840 and 1843, Joule carefully studied the heat produced by an electric current. From this study, he developed Joule's laws of heating, the first of which is commonly referred to as the Joule effect. Joule's first law expresses the relationship between heat generated in a conductor and current flow, resistance, and time. [1]
A flow that is not a function of time is called steady flow. Steady-state flow refers to the condition where the fluid properties at a point in the system do not change over time. Time dependent flow is known as unsteady (also called transient [8]). Whether a particular flow is steady or unsteady, can depend on the chosen frame of reference.
In thermodynamics, the Joule–Thomson effect (also known as the Joule–Kelvin effect or Kelvin–Joule effect) describes the temperature change of a real gas or liquid (as differentiated from an ideal gas) when it is expanding; typically caused by the pressure loss from flow through a valve or porous plug while keeping it insulated so that no heat is exchanged with the environment.
It was originally defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is also part of the United States customary units . [ 1 ] The SI unit for energy is the joule (J) ; one Btu equals about 1,055 J (varying within the range of 1,054–1,060 J depending on the specific definition of ...