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Topic: Brayton cycle

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In the News (Fri 19 Jul 19)

  Thermodynamic Power Cycles
There are four power cycles that are generally used in the generation of electricity; the Rankine cycle, the Brayton cycle, the Otto cycle, and the Diesel cycle.
In the combustion chamber, the air-fuel mixture is ignited, dramatically increasing the temperature of the mixture.
The two cycles are similar in theory, with one major difference; the Otto cycle is a spark-ignition cycle, whereas the Diesel cycle is a compression ignition cycle.
www.me.gatech.edu /energy/brett/four.htm   (1990 words)

 Heat-actuated space conditioning unit with bottoming cycle - United States Patent 4,347,711
The apparatus of claim 1 further comprising a surge valve connected between the inlet and outlet of the Rankine cycle compressor, and means responsive to the pressure differential across that compressor to open the surge valve upon the development of a surge condition in the compressor.
The apparatus of claim 1 wherein the Brayton cycle circuit includes means defining a flow path for exhaust gas from the combustor to the turbo-compression turbine, thence to the recuperator, and from the outlet of the recuperator through the hot side of the boiler to transfer waste heat to the Rankine cycle circuit.
The Brayton cycle engine is energized by the burning of natural gas and includes a combustor, a turbine and compressor on a common shaft, and a recuperator.
xrint.com /patents/us/4347711   (4293 words)

 Improving an Air-Standard Power Cycle
Unlike in liquid-vapor compression cycles such as a Rankine Cycle, the work needed to compress the working fluid in an air standard cycle is a large fraction of the work extracted by the turbine (often over 50%).
A Brayton cycle is the air-standard analog of the Rankine cycle.
The Carnot cycle is maximally efficient because it receives all of its heat addition at the same temperature, which is the highest temperature in the cycle and rejects all of its heat at the lowest temperature in the cycle.
www.qrg.northwestern.edu /thermo/design-library/airstd/brayton.html   (2106 words)

 Advanced Power Conversion Cycles | Nuclear Research   (Site not responding. Last check: 2007-10-02)
Cycle heat exchangers (recuperators and precooler) that use compact heat exchanger printed circuit technology were evaluated.
The current reference cycle for a Gas Cooled Fast Reactor (GCFR) and its operating conditions are described and the cycle is compared to its principal competitors: the steam Rankine cycle (in its superheated and supercritical versions) and the helium Brayton cycle.
The superiority of the supercritical CO recompression Brayton cycle in the turbine inlet temperature range of 500 – 700 °C is demonstrated.
web.mit.edu /canes/research/anp/advpowerconvcycles.html   (656 words)

 Aircraft Propulsion - Level 3 - Gas Turbine Operation and Design Requirements(Gas Turbine Cycles)
The cycle usually describes the relationship between the space occupied by the air in the system (called volume, V) and the pressure (P) it is under.
Brayton cycle pressure-volume diagram for a unit mass of working fluid (e.g., air), showing work (W) and heat (Q) inputs and outputs.
In the closed cycle system, combustion cannot be sustained and the normal combustor is replaced with a second heat exchanger to heat the compressed air before it enters the turbine.
www.allstar.fiu.edu /aero/turbine3.html   (722 words)

 Battery Charger
Since the closed Brayton cycle is fundamentally less dependent on storage, it requires less battery weight to support it than its Diesel equivalent for the same set of operating parameters.
Depending on the vehicle designers’ points of view, the closed Brayton cycle lends itself better to vehicle architectures in which the propulsion part of the vehicle forms a base onto which a wide variety of vehicle bodies can be mounted.
Since closed Brayton cycle endurance figures are several times that of reciprocating engines and probably better that PEM fuel cells, the same base could be used for numerous model upgrades of the same vehicle.
www.cre8tivenergy.com /autohev.html   (3603 words)

 Center for Advanced Nuclear Energy Systems (CANES) | Publications | Abstracts | Advanced Nuclear Power (ANP) Program
It achieves cycle efficiencies on the order of ~45% for the turbine inlet temperature of 550ºC and it is extremely compact and simple – factors key to good economy.
The simple supercritical CO Brayton cycle without intercooling is capable of achieving a cycle efficiency of ~40% at 550ºC and 20 MPa and more than 45% at 650ºC and 30 MPa.
The superiority of the supercritical CO recompression Brayton cycle in the turbine inlet temperature range of 500 – 700ºC is demonstrated.
web.mit.edu /canes/publications/abstracts/anp/anp-090.html   (401 words)

 Fact Sheets > What are Heat Engines?   (Site not responding. Last check: 2007-10-02)
Practical heat engines operate on less efficient cycles (such as the Rankine, Brayton, or Stirling) but in general, the highest thermal efficiency is achieved when the input temperature is as high as possible and the sink temperature is as low as possible.
The Rankine cycle system uses a liquid that evaporates when heated and expands to produce work, such as turning a turbine, which when connected to a generator, produces electricity.
Brayton cycle systems, which incorporate a turbine, also use a gas as the working medium.
www.fact-sheets.com /science-nature/energy/heat_engines   (840 words)

 Turbine Engine Thermodynamic Cycle - Brayton Cycle
It is possible to perform a series of processes, in which the state is changed during each process, but the gas eventually returns to its original state.
Such a series of processes is called a cycle and forms the basis for understanding engine operation.
The area under the T-s diagram is proportional to the useful work and thrust generated by the engine.
www.grc.nasa.gov /WWW/K-12/airplane/brayton.html   (583 words)

 Brayton cycle - Wikipedia, the free encyclopedia
In 1872, Brayton filed a patent for his "Ready Motor" which, unlike the Otto or Diesel cycles, used a separate compressor and expansion cylinder.
Like other internal combustion power cycles, The Brayton cycle is an open system, though for thermodynamic analysis it is conventionally assumed that the exhaust gases are reused in the intake, enabling analysis as a closed system.
In the original 19th-century Brayton engine, ambient air is drawn into a piston compressor, where it is compressed; ideally an isentropic process.
en.wikipedia.org /wiki/Brayton_cycle   (625 words)

 The Herald News - R.I. hits Brayton Point over heat emissions   (Site not responding. Last check: 2007-10-02)
Brayton Point is only about 38 percent efficient, meaning that roughly 62 percent of the energy from the burning fuel is discharged into the environment, mainly as wasted heat, Healey said.
Brayton Point relies on Mount Hope Bay both as a source for the billions of gallons of water it needs to cool its generators and as a dumping ground for the trillions of BTUs of waste heat it discharges, according to Healey.
Brayton Point is also arguing that due to the EPA’s proposed new regulations for cooling water intake structures for existing facilities, the Environmental Appeals Board cannot rule until those regulations are finalized.
www.heraldnews.com /site/news.cfm?newsid=10712999&BRD=1710&PAG=461&dept_id=99784&rfi=6   (1049 words)

 Brayton or Joule Cycle   (Site not responding. Last check: 2007-10-02)
Brayton cycle is an ideal air standard cycle for the closed cycle gas turbine unit.
Both the heat supplied and rejected from the cycle occur at constant pressure, therefore this cycle is also known as constant pressure cycle.
The thermal efficiency of a Brayton cycle with a perfect gas as working fluid is:
www.taftan.com /thermodynamics/BRAYTON.HTM   (103 words)

 Brayton Cycle
A turbine operates on the principal of the Brayton Cycle, which is defined as a constant pressure cycle, with four basic operations which it accomplishes simultaneously and continuously for an uninterrupted flow of power.
The Carnot Cycle has been described as being the most efficient thermal cycle possible, wherein there is no heat losses, and consisting of four reversible processes, two isothermal and two adiabatic.
The Rankine cycle is a thermodynamic cycle used to generate electricity in many power stations, and is the real-world approach to the Carnot cycle.
www.cogeneration.net /Brayton_Cycle.htm   (830 words)

 Ericsson cycle - Wikipedia, the free encyclopedia
The second cycle he developed called the Ericsson Cycle is often compared to the Stirling Cycle because of its external combustion capabilities, use of a regenerator and the high potential efficiency, being equivalent to the Sterling and the Carnot.
Brayton engines were for the most part an internal combustion versions of the Ericsson.
The "Brayton Cycle" is now known as the gas turbine cycle, which differs from the original "Brayton Cycle" in the use of a turbine compressor and expander.
en.wikipedia.org /wiki/Ericsson_cycle   (753 words)

 non pulsed otto cycle engine   (Site not responding. Last check: 2007-10-02)
I mean the ideal Otto cycle (which does not take into account the intake and exhaust strokes) which is essentially adiabatic compression, constant volume burning, adiabatic expansion and finally heat rejection at constant volume.
KM Even the continuous burn Brayton cycle has some pulsation at the 'output' simply because of the presence of the 'buckets' or 'teeth', or whatever it uses to derive power.
To date that is the definition of Brayton Cycle (Who knows, in the future there may be a new ICE cycle discovered that is also continuous burn), and it is the main differentiator from the timed-combustion engines, like the Otto and Diesel cycles.
www.physicsforums.com /showthread.php?t=82566   (1383 words)

 Ideal Heat Engine Gas Cycles
Adiabatic, isentropic expansion of gases in the cylinder after fuel mixture is ignited.
This is the part of the cycle that does positive work.
Heat is transferred from the working gas to an energy storage device at a constant pressure.
www.ac.wwu.edu /~vawter/PhysicsNet/Topics/ThermLaw2/Entropy/GasCycleEngines.html   (242 words)

 5: The Brayton Cycle
The operation of ramjet and gas turbine ("jet") engines can be expressed, in its most basic form, as a "Brayton Cycle" or "Gas Turbine Cycle".
Net heat input   = heat put in during Sep (2), assuming that we don't pay to cool the air, and cannot recover the heat that is lost in the exhaust gases.
To get a given thrust with high propulsive efficiency, it is thus better to accelerate a large mass flow rate through a small velocity increment, than to accelerate a small mass flow rate through a large velocity increment.
www.adl.gatech.edu /classes/propulsion/prop5.html   (448 words)

Just as operating the Rankine cycle with superheat in reverse leads to the vapor-compression cycle, the Brayton power cycle can be operated in reverse to yield the reverse Brayton cycle.
The reverse Brayton cycle is commonly used in aircraft cabin air conditioning systems.
The refrigeration cycles discussed thus far require a significant work input, which is most often supplied in the form of electricity and can result in high operating costs.
wiley.com /college/schmidt/047114343X/thermonet/chp_11/c11s6b0_10.html   (230 words)

The tables for the reheat cycle are given first followed by the cycle with reheat, which we will refer to as the simple cycle.
Note that states 1, 2 and 3 and the processes 1->2 and 2->3 are identical for the cycle with reheat and the cycle without reheat.
We have ignored this effect in the problem by using ideal relationships in the cycle analysis, and by assuming all turbine stages have the same efficiency in all cases.
www.wiley.com /college/schmidt/047114343X/thermonet/chp_9/ex9s6_20.html   (566 words)

 StarRotor Corp. FAQ
However, because the Otto cycle pressures are high compared to the Brayton cycle (which we use), sealing was a problem.
The gaps are small enough that the amount of gas leaked is very small compared to the amount of gas processed, such as in conventional Brayton cycle engines that employ turbines where there is a gap between the blade tip and housing.
Engineers working on Brayton cycle engines focus on axial fans and would likely dismiss the gerotor because it appears not to be able to process large volumes of gas.
www.starrotor.com /FAQ.htm   (958 words)

 Vapor compression and gas refrigeration daemon
Example: A vapor-compression cycle with steam is executed on top of a vapor-compression cycle with R-12 as the working fluid.
Example: Reversed Brayton cycle with a working fluid that must be modeled as a mixture of gases.
Example: A vapor-compression refrigeration cycle with R-12 is executed on top of a reversed Brayton cycle with nitrogen as the working fluid.
energy.sdsu.edu /testcenter/testhome/Test/solve/systems/open/osss/specific/refricycle/refricycle.html   (263 words)

The tables for the intercooling cycle are given first followed by the cycle with intercooling, which we will refer to as the simple cycle.
Note that states 1, 2 and 3 and the processes 1->2 and 2->3 are identical for the cycle with intercooling and the cycle without intercooling.
However, the net heat added to the cycle is also larger when intercooling is added (you can see this by comparing the T-s diagram for this problem with that without intercooling), and the ratio of wnet/qin is lower with intercooling.
www.wiley.com /college/schmidt/047114343X/thermonet/chp_9/ex9s6_25.html   (678 words)

 SDI CONVERSION CYCLES - Nuclear Thermal Propulsion
The most common terrestrial application of this cycle is in coal-fired and nuclear electrical power plants, in which the working fluid is water which is heated to form steam which drives turbine generators.
The primary advantage of the Rankine Cycle is high efficiency, and isothermal heat rejection, which minimizes the area of a radiator for a given operating temperature.
This concept operates on the basis of an evaporation-condensation cycle, in which the gaseous circulating coolant is returned to the liquid phase as it passes through a heat exchanger connected to the radiator.
www.fas.org /nuke/space/c06sdi_3.htm   (6046 words)

 Brayton-Cycle Power-Conversion Unit Tested With Ion Thruster
The test demonstrated end-to-end power throughput and marked the first-ever coupling of a Brayton turboalternator and a gridded ion thruster, both of which are candidates for use on JIMO-type missions.
The testing was conducted at Glenn's Vacuum Facility 6, where the Brayton unit was installed in the 3-m-diameter vacuum test port and the ion thruster was installed in the 7.6-m-diameter main chamber.
The Brayton test unit was a fully integrated power-conversion system including a turboalternator, recuperator, and gas cooler with helium-xenon working fluid designed for operation up to 2 kW.
www.grc.nasa.gov /WWW/RT/2004/RP/RPT-hervol.html   (560 words)

 Green Car Congress: A Compact Brayton-Cycle Engine and Biomass Process for Mixed-Alcohol Fuels
Brayton cycle engines have a high power density (hence their use in jet aircraft), compared to the lower power density of Otto (spark ignition) and Diesel engines.
The major challenge in implementing Brayton cycle engines, according to an analysis done for the Defense Advanced Research Projects Agency by Holtzapple, is to find a means to process large volumes of air to achieve a desired power output.
The patented StarRotor Brayton cycle engine uses gerotors for both the compressor and expander.
www.greencarcongress.com /2006/04/a_braytoncycle_.html   (3180 words)

 Turbx Technology Reviews
Indeed, preliminary analysis of the ideal cycle thermodynamics by ORNL personnel shows that this version of the Atkinson cycle has a power density per unit mass of working fluid greater than that of the ideal Brayton cycle for a given compression ratio.
The Diesel, Brayton and the Otto cycle engines are known to be very compact and reliable prime movers.
The Atkinson cycle (as implemented by TurbX*) is our recommendation as the most suitable engine to pursue even though it is the least mature of the three.
www.turbx.com /Reviews.htm   (1297 words)

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