Einfluß von Einlaufeffekten auf den Wärmeübergang bei laminarer oszillierender Rohrströmung

Abstract

A theoretical analysis was performed to evaluate the influence of developing flow on the heat transfer associated with laminar oscillating pipe flow. Simplified analytical approaches are briefly discussed before an investigation based on the numerical solution of the conservation equations for mass, momentum and energy is presented, assuming constant wall temperature and an incompressible viscous fluid. Focusing on operating conditions as found in heat exchangers of regenerative thermal machines, like Stifling engines or Vuilleumier heat pumps, numerous calculations of the flow field and the heat transfer have been executed covering wide ranges of the characteristic dimensionless groups. The results are presented in terms of correlations of the mean Nusselt number averaged on the pipe length and a distribution function describing the local heat transfer. Furthermore, it is shown that the derived correlations are also applicable to compressible fluid flow, provided that the relative pressure amplitude is within the limits typical of regenerative thermal machines.

Effects of Flow Pulsation on Forced Convection in a Channel Containing Regularly Spaced Nonconducting Fins

“…Analytical and numerical analysis for laminar pipe flow showed that the influence of pulsation on Nu is more pronounced in the entrance region of the pipe and small at the downstream end [9,18,21,22,25]. The same observation was made by Habib et al [20] in their experimental investigation.…”

Numerical correlation for the pressure drop in Stirling engine heat exchangers

“…They obtained good results predicting laminar flow and fully turbulent regime, but they did not obtain adequate results for transition flow regime. The heat transfer of reciprocating laminar pipe flow has been studied numerically by different authors [12,23]. In the high Reynolds number range, Su et al [24] studied the enhancement of the heat transfer due to reciprocating flow using the Saffman's RANS turbulence model while Walther [25] considered a lo Reynolds number keε turbulence model.…”

Mechanically Driven Oscillating Flow Cooling Loops – A Review

“…(18) and (19) need to be decomposed to yield the real part explicitly. Significant effort has been undertaken to visualize the flow and thereby verify the solution using various experiments (Harris, Peev, and Wilkinson, 1969;Walther et al, 1998;Simon and Seume, 1988). In Simon and Seume, (1988) plots of velocity profiles for laminar, incompressible, fully developed, and oscillating flow for eight dimensionless frequencies have been provided.…”

“…In Simon and Seume, (1988) plots of velocity profiles for laminar, incompressible, fully developed, and oscillating flow for eight dimensionless frequencies have been provided. Fig 4 shows the variation of velocity profiles in laminar oscillating pipe flow with time during one cycle Walther et al, (1998).…”

“…Variation of velocity profiles in laminar oscillating pipe flow with time during one cycle. Fluid accelerated to the right and left shown respectively by the solid and dashed linesWalther et al, (1998) Frontiers inHeat and Mass Transfer (FHMT), 13, 17 (2019) DOI: 10.5098/hmt.13…”