November 13, 2018
Although shell and tube systems receive a big chunk of coverage in engineering articles, they're not the only heat exchangers on the market. There are plate heat exchangers, regenerative models, and several disparate fluid-energy trading solutions available, so let's give them their chance to shine. The exposition begins now, with a review of shell and tube systems, for they've become something of a benchmark option.
As the label implies, there's a pressure vessel covering a tube stack. Inside the cylindrical "shell," one fluid flows. The tubes, bundled together, transport the second fluid. Think of how the tubes fold surface geometry. If the stack were to be unfolded, then the larger surface area would become obvious. Available in alternating tube configurations, the vessel design uses direct and crossflow design architectures to optimize a vessel's energy transference traits.
The above heat exchanger type never mixes its two fluid or vapour mediums. If a small amount of mixing is allowable, then adiabatic wheels can be utilized, with their threaded discs rotating through cold and hot fluidic broths to facilitate the energy exchanging cycle. Commonly used in food processing and petroleum applications, this design employs internally mounted wheels, which store heat in an intermediate fluid load. Clearly, possessing so many active moving parts, adiabatic wheel heat exchangers require next-level engineering skills.
In this vessel architecture, intricate curving channels dominate the systems structure. Hot water, just as one example, flows along both sides of a conventional heat exchanger layout. Exiting the vessel hot, energy is transferred to the following stream of cooler incoming water, hence the regenerative effect. Creating cyclical thermal energy transference, this configuration is used to pre-heat power station turbines, to process petroleum distillates, and even to assist cryogenics refrigeration units.
Substituting shell tubes with thin stainless steel plates, the curving geometry opens up to form open-area rectangles. Thin gaps exist between the rows of plates. Energy is traded between two fluid sources, through the plates, and between the thin gaps. Openings are cut into the corners of the rectangular plates, which permit the heat-leeching channels passage. This type of heat trading vessel finds as much use in cooling applications as it does heat transference ones.
It's not all plain sailing, not when pressure vessel engineers have so many heat exchanging principles to tackle. Then the options divide further. There are U-shaped tube stacks and other configurations. For the regenerative models, intricate flow managing designs ensure the heat cycling effect continues unabated. As for adiabatic heat exchangers, well, that rotating wheel can't function properly without the aid of a number of perfectly fabricated components.
Fusion - Weld Engineering Pty Ltd
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1865 Frankston Flinders Road,
Hastings, VIC 3915
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