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Thermodynamic Power Cycle
A thermodynamic cycle consists of linked sequences of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the system to its initial state. In the process of passing through a cycle, the working fluid (system) may convert heat from a warm source into useful work, and dispose of the remaining heat to a cold sink, thereby acting as a heat engine. Conversely, the cycle may be reversed and use work to move heat from a cold source and transfer it to a warm sink thereby acting as a heat pump. If at every point in the cycle the system is in thermodynamic equilibrium, the cycle is reversible. Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities (o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic System
A thermodynamic system is a body of matter and/or radiation separate from its surroundings that can be studied using the laws of thermodynamics. Thermodynamic systems can be passive and active according to internal processes. According to internal processes, passive systems and active systems are distinguished: passive, in which there is a redistribution of available energy, active, in which one type of energy is converted into another. Depending on its interaction with the environment, a thermodynamic system may be an isolated system, a Closed system#In thermodynamics, closed system, or an Open system (systems theory), open system. An isolated system does not exchange matter or energy with its surroundings. A closed system may exchange heat, experience forces, and exert forces, but does not exchange matter. An open system can interact with its surroundings by exchanging both matter and energy. The physical condition of a thermodynamic system at a given time is described by its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanical Work
In science, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force strength and the distance traveled. A force is said to do ''positive work'' if it has a component in the direction of the displacement of the point of application. A force does ''negative work'' if it has a component opposite to the direction of the displacement at the point of application of the force. For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is positive, and is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). If the ball is thrown upwards, the work done by the gravitational force is negative, and is equal to the weight multiplied by the displacement in the upwards direction. Both force and displace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polytropic Process
A polytropic process is a thermodynamic process that obeys the relation: p V^ = C where ''p'' is the pressure, ''V'' is volume, ''n'' is the polytropic index, and ''C'' is a constant. The polytropic process equation describes expansion and compression processes which include heat transfer. Particular cases Some specific values of ''n'' correspond to particular cases: * n=0 for an isobaric process, * n=+\infty for an isochoric process. In addition, when the ideal gas law applies: * n=1 for an isothermal process, * n=\gamma for an isentropic process. Where \gamma is the ratio of the heat capacity at constant pressure (C_P) to heat capacity at constant volume (C_V). Equivalence between the polytropic coefficient and the ratio of energy transfers For an ideal gas in a closed system undergoing a slow process with negligible changes in kinetic and potential energy the process is polytropic, such that p v^ = C where ''C'' is a constant, K = \frac, \gamma = \frac, and with the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isenthalpic Process
An isenthalpic process or isoenthalpic process is a process that proceeds without any change in enthalpy, ''H''; or specific enthalpy, ''h''. Overview If a steady-state, steady-flow process is analysed using a control volume, everything outside the control volume is considered to be the ''surroundings''.G. J. Van Wylen and R. E. Sonntag, ''Fundamentals of Classical Thermodynamics'', Section 2.1 (3rd edition). Such a process will be isenthalpic if there is no transfer of heat to or from the surroundings, no work done on or by the surroundings, and no change in the kinetic energy of the fluid.G. J. Van Wylen and R. E. Sonntag, ''Fundamentals of Classical Thermodynamics'', Section 5.13 (3rd edition). This is a sufficient but not necessary condition for isoenthalpy. The necessary condition for a process to be isoenthalpic is that the sum of each of the terms of the energy balance other than enthalpy (work, heat, changes in kinetic energy, etc.) cancel each other, so that the enthalpy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isentropic
An isentropic process is an idealized thermodynamic process that is both adiabatic and reversible. The work transfers of the system are frictionless, and there is no net transfer of heat or matter. Such an idealized process is useful in engineering as a model of and basis of comparison for real processes. This process is idealized because reversible processes do not occur in reality; thinking of a process as both adiabatic and reversible would show that the initial and final entropies are the same, thus, the reason it is called isentropic (entropy does not change). Thermodynamic processes are named based on the effect they would have on the system (ex. isovolumetric: constant volume, isenthalpic: constant enthalpy). Even though in reality it is not necessarily possible to carry out an isentropic process, some may be approximated as such. The word "isentropic" derives from the process being one in which the entropy of the system remains unchanged. In addition to a process wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isochoric Process
In thermodynamics, an isochoric process, also called a constant-volume process, an isovolumetric process, or an isometric process, is a thermodynamic process during which the volume of the closed system undergoing such a process remains constant. An isochoric process is exemplified by the heating or the cooling of the contents of a sealed, inelastic container: The thermodynamic process is the addition or removal of heat; the isolation of the contents of the container establishes the closed system; and the inability of the container to deform imposes the constant-volume condition. Formalism An isochoric thermodynamic quasi-static process is characterized by constant volume, i.e., .Ansermet, J.-P., Brechet, S.D. (2019). ''Principles of Thermodynamics'', Cambridge University Press, Cambridge UK, p. 113. The process does no pressure-volume work, since such work is defined by W = P \Delta V , where is pressure. The sign convention is such that positive work is performed by the sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isobaric Process
In thermodynamics, an isobaric process is a type of thermodynamic process in which the pressure of the Thermodynamic system, system stays constant: Δ''P'' = 0. The heat transferred to the system does work (thermodynamics), work, but also changes the internal energy (''U'') of the system. This article uses the physics sign convention for work, where positive work is work (thermodynamics)#Sign convention, work done by the system. Using this convention, by the first law of thermodynamics, : Q = \Delta U + W\, where ''W'' is work, ''U'' is internal energy, and ''Q'' is heat. Pressure-volume work by the closed system is defined as: :W = \int \! p \,dV \, where Δ means change over the whole process, whereas ''d'' denotes a differential. Since pressure is constant, this means that : W = p \Delta V\, . Applying the ideal gas law, this becomes : W = n\,R\,\Delta T with ''R'' representing the gas constant, and ''n'' representing the amount of substance, which is ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothermal
An isothermal process is a type of thermodynamic process in which the temperature ''T'' of a system remains constant: Δ''T'' = 0. This typically occurs when a system is in contact with an outside thermal reservoir, and a change in the system occurs slowly enough to allow the system to be continuously adjusted to the temperature of the reservoir through heat exchange (see quasi-equilibrium). In contrast, an ''adiabatic process'' is where a system exchanges no heat with its surroundings (''Q'' = 0). Simply, we can say that in an isothermal process * T = \text * \Delta T = 0 * dT = 0 * For ideal gases only, internal energy \Delta U = 0 while in adiabatic processes: * Q = 0. Etymology The noun '' isotherm'' is derived from the Ancient Greek words (), meaning "equal", and (), meaning "heat". Examples Isothermal processes can occur in any kind of system that has some means of regulating the temperature, including highly structured machines, and even living cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ordinate
In mathematics, the abscissa (; plural ''abscissae'' or ''abscissas'') and the ordinate are respectively the first and second coordinate of a point in a Cartesian coordinate system: : abscissa \equiv x-axis (horizontal) coordinate : ordinate \equiv y-axis (vertical) coordinate Together they form an ordered pair which defines the location of a point in two-dimensional rectangular space. More technically, the abscissa of a point is the signed measure of its projection on the primary axis. Its absolute value is the distance between the projection and the origin of the axis, and its sign is given by the location on the projection relative to the origin (before: negative; after: positive). Similarly, the ordinate of a point is the signed measure of its projection on the secondary axis. In three dimensions, the third direction is sometimes referred to as the '' applicate''. Etymology Though the word "abscissa" () has been used at least since ''De Practica Geometrie'' (1220) by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abscissa
In mathematics, the abscissa (; plural ''abscissae'' or ''abscissas'') and the ordinate are respectively the first and second coordinate of a point in a Cartesian coordinate system: : abscissa \equiv x-axis (horizontal) coordinate : ordinate \equiv y-axis (vertical) coordinate Together they form an ordered pair which defines the location of a point in two-dimensional rectangular space. More technically, the abscissa of a point is the signed measure of its projection on the primary axis. Its absolute value is the distance between the projection and the origin of the axis, and its sign is given by the location on the projection relative to the origin (before: negative; after: positive). Similarly, the ordinate of a point is the signed measure of its projection on the secondary axis. In three dimensions, the third direction is sometimes referred to as the '' applicate''. Etymology Though the word "abscissa" () has been used at least since ''De Practica Geometrie'' (1220) by F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
