IF YOU are reading this while sitting in an aircraft and are of a nervous disposition, do not be alarmed, but the temperature inside the jet engines keeping you aloft probably exceeds the melting point of the materials that those engines are made from. That they do not consequently turn into a molten mess is a feat of modern engineering. It involves a combination of tough alloys and advanced production techniques, such as 3D printing, which allow components to be made with tiny channels through which cooling air circulates. Parts exposed to the most extreme temperatures, which can reach more than 1,300°C, are given additional protection with a coating of special heat-resisting ceramics.
New jet engines are designed to run hot because that results in a more complete combustion, which lowers fuel consumption and cuts emissions. Hot engines, though, need nurturing. Nowadays the three big aircraft-engine makers, General Electric (GE), Rolls-Royce and Pratt & Whitney, usually include...Continue reading
Source: Science and technology http://ift.tt/2x0cmN8
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