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Cryogenic engineering is a sub stream of mechanical engineering dealing with cryogenics, and related very low temperature processes such as air liquefaction, cryogenic engines (for rocket propulsion), cryosurgery. Generally, temperatures below the boiling point of Nitrogen (77 K) comes under the purview of cryogenic engineering. Cryogenics may be considered as the recent advancement in the field of refrigeration. Though there is no fixed demarcation as to where refrigeration ends and cryogenics begins even then for general reference temperature below 150c(120k) are considered as cryogenic temperature. The four gases which mainly contribute for cryogenic application and research are (O2-B.P.90K), (N2-B.P.77K), (Helium-B.P.4.2k) & (H2-B.P.20K). The word cryogenics is derived from two Latin words. Cryo - means cold and Genics - means science. Cryogenics is the science of cold.
The term Cryogenics originates from Greek word which means creation or production by means of cold. As prices for energy and raw materials rise and concern for the environment makes safe waste disposal difficult and costly, resource recovery becomes a vital matter for today s business.
Cryogenic grinding technology can efficiently grind most tough materials and can also facilitate Cryogenic recycling of tough composite materials and multi component scrap. The heart of this technology is the CRYO-GRIND SYSTEM. It employs a cryogenic process to embrittle and grind materials to achieve consistent particle size for a wide range of products. The cryogenic process also has a unique capability for recycling difficult to separate composite materials.
Cryogenic grinding is a method of powdering herbs at sub-zero temperatures ranging from 0 to minus 70 F. The herbs are frozen with liquid nitrogen as they are being ground. This process does not damage or alter the chemical composition of the plant in any way. Normal grinding processes which do not use a cooling system can reach up to 200 F. These high temperatures can reduce volatile components and heat-sensitive constituents in herbs. The cryogenic grinding process starts with air-dried herbs, rather than freeze-dried herbs.
Solid materials are ground or pulverized by way of hammer mills, attrition mills, granulators or other equipment. A smaller particle size is usually needed to enhance the further processing of the solid, as in mixing with other materials. A finer particle also helps in melting of rubber and plastics for molding. However, many materials are either very soft or very tough at room temperatures. By cooling to cryogenic temperatures with liquid nitrogen, these may be embrittled and easily fractured into small particles.
Cryogenic engineering is a sub stream of mechanical engineering dealing with cryogenics, and related very low temperature processes such as air liquefaction, cryogenic engines (for rocket propulsion), cryosurgery. Generally, temperatures below the boiling point of Nitrogen (77 K) comes under the purview of cryogenic engineering. Cryogenics may be considered as the recent advancement in the field of refrigeration. Though there is no fixed demarcation as to where refrigeration ends and cryogenics begins even then for general reference temperature below 150c(120k) are considered as cryogenic temperature. The four gases which mainly contribute for cryogenic application and research are (O2-B.P.90K), (N2-B.P.77K), (Helium-B.P.4.2k) & (H2-B.P.20K). The word cryogenics is derived from two Latin words. Cryo - means cold and Genics - means science. Cryogenics is the science of cold.
The term Cryogenics originates from Greek word which means creation or production by means of cold. As prices for energy and raw materials rise and concern for the environment makes safe waste disposal difficult and costly, resource recovery becomes a vital matter for today s business.
Cryogenic grinding technology can efficiently grind most tough materials and can also facilitate Cryogenic recycling of tough composite materials and multi component scrap. The heart of this technology is the CRYO-GRIND SYSTEM. It employs a cryogenic process to embrittle and grind materials to achieve consistent particle size for a wide range of products. The cryogenic process also has a unique capability for recycling difficult to separate composite materials.
Cryogenic grinding is a method of powdering herbs at sub-zero temperatures ranging from 0 to minus 70 F. The herbs are frozen with liquid nitrogen as they are being ground. This process does not damage or alter the chemical composition of the plant in any way. Normal grinding processes which do not use a cooling system can reach up to 200 F. These high temperatures can reduce volatile components and heat-sensitive constituents in herbs. The cryogenic grinding process starts with air-dried herbs, rather than freeze-dried herbs.
Solid materials are ground or pulverized by way of hammer mills, attrition mills, granulators or other equipment. A smaller particle size is usually needed to enhance the further processing of the solid, as in mixing with other materials. A finer particle also helps in melting of rubber and plastics for molding. However, many materials are either very soft or very tough at room temperatures. By cooling to cryogenic temperatures with liquid nitrogen, these may be embrittled and easily fractured into small particles.
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Background:
The cryogenic engine gets its name from the extremely cold temperature at which liquid nitrogen (the fuels used) is stored.
The Space Shuttle's main engines used for liftoff are cryogenic engines. The Shuttle's smaller thrusters for orbital manuvering use non-cyogenic hypergolic fuels, which are compact and are stored at warm temperatures. Currently, only the United States, Russia, China, France, Japan and India have mastered cryogenic rocket technology.
Cryogenic fuels:
Cryogenic fuels are fuels that require storage at extremely low temperatures in order to maintain them in a liquid state. These fuels are used in the machinery that operate in space (For example - Rocket ships, Satellites, etc.) because ordinary fuel cannot be used there, due to absence of environment that supports combustion .Cryogenic fuels most often Constitute liquefied gases such as liquid hydrogen, Liquid natural gas, liquid methane.
In a cryogenic propellant, the fuel and the oxidizer are in the form of very cold, liquefied gases. These liquefied gases are referred to as super cooled as they stay in liquid form even though they are at a temperature lower than the freezing point. Thus we can say that super cooled gases used as liquid fuels are called cryogenic fuels.
WORKING:
Cryogenic Engines are rocket motors designed for liquid fuels that have to be held at very low "cryogenic" temperatures to be liquid - they would otherwise be gas at normal temperatures. Typically Hydrogen and Oxygen are used which need to be held below 20 K (-423 F) and 90 K (-297 F) to remain liquid.
The engine components are also cooled so the fuel doesn't boil to a gas in the lines that feed the engine. The thrust comes from the rapid expansion from liquid to gas with the gas emerging from the motor at very high speed. The energy needed to heat the fuels comes from burning them, once they are gasses. Cryogenic engines are the highest performing rocket motors. One disadvantage is that the fuel tanks tend to be bulky and require heavy insulation to store the propellant. Their high fuel efficiency, however, outweighs this disadvantage.
The cryogenic engine gets its name from the extremely cold temperature at which liquid nitrogen is stored. Air moving around the vehicle is used to heat liquid nitrogen to a boil. Once it boils, it turns to gas in the same way that heated water forms steam in a steam engine. A rocket like the Ariane 5 uses oxygen and hydrogen, both stored as a cryogenic liquid, to produce its power. The liquid nitrogen, stored at -320 degrees Fahrenheit, is vaporized by the heat exchanger. Nitrogen gas formed in the heat exchanger expands to about 700 times the volume of its liquid form. This highly pressurized gas is then fed to the expander, where the force of the nitrogen gas is converted into mechanical power.
POWER CYCLES
There are basically 4 power cycles:
Pressure-Fed Cycle
Expander cycle
Gas-generator cycle
Staged combustion cycle
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Cryogenics is the world's leading journal focusing on all aspects of cryoengineering and cryogenics.
Papers published in Cryogenics cover a wide variety of subjects in low temperature engineering and
research. Among the areas covered are:
Applications of superconductivity: magnets, electronics, devices
Superconductors and their properties
Properties of materials: metals, alloys, composites, polymers, insulations
New applications of cryogenic technology to processes, devices, machinery
Refrigeration and liquefaction technology
Thermodynamics
Fluid properties and fluid mechanics
Heat transfer
Thermometry and measurement science
Cryogenics in medicine
Cryoelectronics
As well as original research papers, Cryogenics contains commissioned review articles on the latest
developments in cryogenics worldwide, research and technical notes describing preliminary results
and experimental details, and letters to the Editor on recent areas of discussion and controversy.
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Cryogenic engineering is a sub stream of mechanical engineering dealing with cryogenics, and related very low temperature processes such as air liquefaction, cryogenic engines (for rocket propulsion), cryosurgery. Generally, temperatures below the boiling point of Nitrogen (77 K) comes under the purview of cryogenic engineering. Cryogenics may be considered as the recent advancement in the field of refrigeration. Though there is no fixed demarcation as to where refrigeration ends and cryogenics begins even then for general reference temperature below 150c(120k) are considered as cryogenic temperature. The four gases which mainly contribute for cryogenic application and research are (O2-B.P.90K), (N2-B.P.77K), (Helium-B.P.4.2k) & (H2-B.P.20K). The word cryogenics is derived from two Latin words. Cryo - means cold and Genics - means science. Cryogenics is the science of cold.
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Today we will share the notes for mechanical engineering notes for all semesters all subject in pdf format so that student s can easily download and study well.Engineering books sometimes are not the best option so here are the lecture written notes for Electronics and communications Engineering VTU students.Download free and get good grades in your academics and stay tuned for more updates and don t forget to subscribe to our newsletter and DO visit our forum for discussion and solving your queries by experts
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Hi am saurav i would like to get details on mechanical cryogenics notes for vtu 7th semester ..My friend sumit said mechanical cryogenics notes for vtu 7th semester will be available here and now i am living atbangalore , yelehanka and i last studied in the college/school SAIT and now am doing engineering .
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To get data about it please visit the given page link :
http://vtunotes2010.blogspotp/notes-for-...civil.html
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hii i need a cryogenics notes bcz no books available in collage libarery or outside so plz provide the good notes
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Needed cryogenics notes and study material for 7th sem mechanical engineering
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Please release vtu seventh semester cryogenics notes as early as possible
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