Brayton cycle - Revision history

Michel Lamontagne at 21:34, 27 November 2023

2023-11-27T21:34:12Z

2023-11-27T21:33:11Z

2023-11-27T21:31:40Z

2023-11-27T21:22:41Z

2022-10-04T23:59:39Z

2022-10-04T23:57:00Z

References

2022-10-04T23:56:36Z

added reference. and a bit more info.

2022-10-04T23:51:45Z

Mars is cold, which is a good thing?

2022-10-02T18:10:52Z

2022-10-02T18:10:26Z

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 *The ideal equation for a Brayton cycle is efficiency(ef) = 1-Tc/Th.
-*An actual Brayton engine has a number of inefficiencies and non-reversible, so the actual efficiency is significantly lower.
+*A real Brayton engine has a number of inefficiencies and non-reversible, so the actual efficiency is significantly lower.
 For a high efficiency Brayton cycle, Th needs to be significantly higher than Tc.

@@ Line 2: / Line 2: @@
 In this cycle a hot gas leaves a heat source, turns a turbine, is cooled in a heat exchanger, runs through a compressor and returns to the heat source.
-The turbine powers the compressors, and part of the turbine power is used to power a turbo-alternator to make electricity.
+The turbine powers the compressor, and part of the turbine power is used to power a turbo-alternator to make electricity.
 *An airplane turbo engine is an example of an open Brayton cycle.
@@ Line 19: / Line 19: @@
 If applied to a closed cycle used on Mars, Tc is the radiator temperature, and Th would be the temperature of the reactor core.  Note that Mars has large cold sinks, so in principle, heat engines would be more efficient on Mars than on Earth.  However, dumping heat on Earth is easier (into the air and rivers), so it may be an engineering challenge to dump large amounts of waste heat on Mars.
-The Rankine cycle is a common alternative cycle, using phase change from gas liquid and back to gas, is used in most thermal electric plants.
+The Rankine cycle is a common alternative cycle, using phase change from gas liquid and back to gas.  It is used in most thermal electric plants and in many cooling/refrigeration cycles.
 ==References==

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-A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium.  (Some alternative cycles use gas to liquid phase changes.)  <ref>https://en.wikipedia.org/wiki/Heat_engine|Wiki write up on thermodynamic cycles and engines</ref>
+A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium and both temperature and pressure changes to move the energy in the cycle. <ref>https://en.wikipedia.org/wiki/Heat_engine|Wiki write up on thermodynamic cycles and engines</ref>
 *An airplane turbo engine is an example of an open Brayton cycle.
@@ Line 15: / Line 18: @@
 If applied to a closed cycle used on Mars, Tc is the radiator temperature, and Th would be the temperature of the reactor core.  Note that Mars has large cold sinks, so in principle, heat engines would be more efficient on Mars than on Earth.  However, dumping heat on Earth is easier (into the air and rivers), so it may be an engineering challenge to dump large amounts of waste heat on Mars.
 ==References==

@@ Line 1: / Line 1: @@
-A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium.  (Some more efficient cycles require gas to liquid phase changes.)  <ref>https://en.wikipedia.org/wiki/Heat_engine|Wiki write up on thermodynamic cycles and engines</ref>
+A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium.  (Some alternative cycles use gas to liquid phase changes.)  <ref>https://en.wikipedia.org/wiki/Heat_engine|Wiki write up on thermodynamic cycles and engines</ref>
 *An airplane turbo engine is an example of an open Brayton cycle.
@@ Line 8: / Line 8: @@
 *An actual Brayton engine has a number of inefficiencies and non-reversible, so the actual efficiency is significantly lower.
-So for a high efficiency Brayton cycle, Th needs to be significantly higher than Tc.
+For a high efficiency Brayton cycle, Th needs to be significantly higher than Tc.
 *For example, with an efficiency of 40% Tc/Th is 0,6.  If Tc is 500K, then Th is 830K.

@@ Line 1: / Line 1: @@
-A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium.  (Some more efficient cycles require gas to liquid phase changes.)
+A heat engine moves heat from a high temperature area (Th), to a lower temperature sink (Tc), in order to generate power.  The Brayton cycle is a thermodynamic engine that can be used for power (usually electric) generation.  It uses a gas as a working medium.  (Some more efficient cycles require gas to liquid phase changes.)  <ref>https://en.wikipedia.org/wiki/Heat_engine|Wiki write up on thermodynamic cycles and engines</ref>
 *An airplane turbo engine is an example of an open Brayton cycle.
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 ==References==

← Older revision		Revision as of 23:57, 4 October 2022
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	==References==		==References==
−	<ref>https://en.wikipedia.org/wiki/Heat_engine\|Wiki write up on thermodynamic cycles and engines>	+	<ref>https://en.wikipedia.org/wiki/Heat_engine\|Wiki write up on thermodynamic cycles and engines</ref>

← Older revision		Revision as of 18:10, 2 October 2022
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	*For the same example at 60% efficiency, Tc/Th=0,4, and for a TC of 500K Th is 1250K.		*For the same example at 60% efficiency, Tc/Th=0,4, and for a TC of 500K Th is 1250K.

−	*If applied to a closed cycle used on Mars, Tc is the radiator temperature, and Th would be the temperature of the reactor core.	+	If applied to a closed cycle used on Mars, Tc is the radiator temperature, and Th would be the temperature of the reactor core.