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Lenoir Cycle
The Lenoir cycle is an idealized thermodynamic cycle often used to model a pulse jet engine. It is based on the operation of an engine patented by Jean Joseph Etienne Lenoir in 1860. This engine is often thought of as the first commercially produced internal combustion engine. The absence of any compression process in the design leads to lower thermal efficiency than the more well known Otto cycle and Diesel cycle. The cycle In the cycle, an ideal gas undergoes :1–2: Constant volume (wikt:isochoric, isochoric) heat addition; :2–3: Isentropic process, Isentropic expansion; :3–1: Constant pressure (isobaric process, isobaric) heat rejection. The expansion process is isentropic process, isentropic and hence involves no heat interaction. Energy is absorbed as heat during the isochoric heating and rejected as work during the isentropic expansion. Waste heat is rejected during the isobaric cooling which consumes some work. Constant volume heat addition (1–2) In the ideal ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lenoir Gas Engine 1860
Lenoir may refer to: Locations * Lenoir, North Carolina, United States * Lenoir County, North Carolina, United States * Lenoir City, Tennessee Universities * Lenoir-Rhyne University * Lenoir Dining Hall, a dining hall at the University of North Carolina at Chapel Hill Other * USS ''Lenoir'' (AKA-74), a World War II attack cargo ship * Lenoir cycle, the basis of the first commercially produced internal combustion engine Names * Lenoir (surname) Lenoir or LeNoire is a surname that may refer to: *Alban Lenoir (born 1980), French actor, screenwriter and stuntman *Alexandre Lenoir (1761–1839), French archaeologist *Billy Lenoir (1942–2007), American tennis player *Charles-Amable Lenoir (1 ... See also * Richard-Lenoir (Paris Metro) {{disambiguation, geo ... [...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] |
Overall Pressure Ratio
In aeronautical engineering, overall pressure ratio, or overall compression ratio, is the amount of times the pressure increases due to ram compression and the work done by the compressor stages. The compressor pressure ratio is the ratio of the stagnation pressures at the front and rear of the compressor of a gas turbine. Overall pressure ratio in a high-bypass turbofan is a function of inlet pressure ratio and compressor pressure ratio: OPR = IPR \times CPR The terms ''compression ratio'' and ''pressure ratio'' are used interchangeably. Advantages of high overall pressure ratios As can be seen in the formula for maximum theoretical thermal efficiency in an ideal Brayton cycle engine, a high pressure ratio leads to higher thermal efficiency: \eta = 1-\left(\frac\right) where PR is the pressure ratio and gamma the heat capacity ratio of the fluid, 1.4 for air. Keep in mind that pressure ratio scales exponentially with the number of compressor stages. Imagine a gas turbin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compression Ratio
The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine. A fundamental specification for such engines, it can be measured in two different ways. The simpler way is the static compression ratio: in a reciprocating engine, this is the ratio of the volume of the cylinder when the piston is at the bottom of its stroke to that volume when the piston is at the top of its stroke. The dynamic compression ratio is a more advanced calculation which also takes into account gases entering and exiting the cylinder during the compression phase. Effect and typical ratios A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air–fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher compression ratios permit the same combustion temperature to be reached wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waste Heat
Waste heat is heat that is produced by a machine, or other process that uses energy, as a byproduct of doing work. All such processes give off some waste heat as a fundamental result of the laws of thermodynamics. Waste heat has lower utility (or in thermodynamics lexicon a lower exergy or higher entropy) than the original energy source. Sources of waste heat include all manner of human activities, natural systems, and all organisms, for example, incandescent light bulbs get hot, a refrigerator warms the room air, a building gets hot during peak hours, an internal combustion engine generates high-temperature exhaust gases, and electronic components get warm when in operation. Instead of being "wasted" by release into the ambient environment, sometimes waste heat (or cold) can be used by another process (such as using hot engine coolant to heat a vehicle), or a portion of heat that would otherwise be wasted can be reused in the same process if make-up heat is added to the sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isentropic Process
An isentropic process is an idealized thermodynamic process that is both Adiabatic process, adiabatic and Reversible process (thermodynamics), reversible. The work (physics), work transfers of the system are friction, 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). Thermodynamics, 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 proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermodynamic Cycle
A thermodynamic cycle consists of linked sequences of thermodynamic processes that involve heat transfer, transfer of heat and work (physics), work into and out of the system, while varying pressure, temperature, and other state variables within the system, and that eventually returns the thermodynamic system, 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 stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isochoric
Isochoric may refer to: *cell-transitive, in geometry *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 ..., a constant volume process in chemistry or thermodynamics * Isochoric model {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
