Heat transfer performance and flow resistance characteristics of a steam-cooled U-shaped channel with concave/convex structure were numerically investigated by standard k-ω turbulent model. The heat transfer correlations were evaluated and analyzed for Reynolds number from 10 000 to 50 000
inlet temperature ratio from 0.79 to 0.93
and outlet pressure from 0.5 to 3 MPa. The different cooling performances of steam and air were discussed. It reveals that the overall heat transfer performance rises while the friction factor falls with the increasing Reynolds number; the increasing inlet temperature ratio effectively enables to reduce the flow resistance and enhance heat transfer performance obviously; the heightening outlet pressure is beneficial to heat transfer enhancement
but it also leads to greatly increased flow resistance. Thus
a combination of moderate steam pressure from 1.5 MPa to 2 MPa
and medium inlet temperature ratio from 0.84 to 0.88 is suggested to achieve an ideal heat transfer performance. The thermophysical properties of steam are more prone to be affected by temperature and pressure compared with those of air. As a result
the heat transfer performance evaluation criterion for steam varies obviously while the Reynolds number exerts slight influence.
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