Inhaltszusammenfassung

A wide variety of spirally corrugated tubes and indented tubes appear suitable, as their microscopic roughness corresponds to that of smooth tubes, yet the wall contour can repeatedly generate macroscopic turbulence, prop-agating heat transfer through conveyance of streamlines from hot areas to colder areas near the wall. The additional forced turbulence would suggest that tube contours exist having a significantly higher average gas-side heat trans-fer coefficients compared to smooth tubes, ...A wide variety of spirally corrugated tubes and indented tubes appear suitable, as their microscopic roughness corresponds to that of smooth tubes, yet the wall contour can repeatedly generate macroscopic turbulence, prop-agating heat transfer through conveyance of streamlines from hot areas to colder areas near the wall. The additional forced turbulence would suggest that tube contours exist having a significantly higher average gas-side heat trans-fer coefficients compared to smooth tubes, with negligibly higher pressure loss and ideally even self-cleaning flow properties. Due to the large variety of possible parameters influencing the flow and temperature boundary layers decisive for heat transfer, there are plans to measure a selection of typical designs of spirally corrugated tubes and indented tubes in a non-isothermal tube test bench with regard to heat transfer properties and pressure loss. With the help of CFD calculations, it should be possible to impute promising wall contours. The study seeks to investigate the influences of the parameters determining the contour, such as tube wall thickness, structure depth, spiral angle, groove spacing and the dependence on the Reynolds number and temperature spread. A validation of the numerical simulation through experimental tests and field measurements must be performed so that the pressure loss and heat transfer coefficient can be reliably determined with high accuracy for new contours.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Strömungsmechanik, Technische Thermodynamik und Thermische Energietechnik

DDC Sachgruppe:
Ingenieurwissenschaften