Numerical Calculation of the Irreversible Entropy Production in Heat Transferring Structures

Abstract

In diesem Beitrag werden zwei verschiedene additiv herstellbare Metallstrukturen hinsichtlich der Entropieproduktionszahl bewertet. Die beiden Strukturen werden bei zwei Temperaturniveaus, 200/80 °C und 700/580 °C, untersucht. Bei dem niedrigen Temperaturniveau ist bei beiden Strukturen insbesondere die Wärmeleitung innerhalb der Struktur der Haupttreiber für die Entropieproduktion. Werden die Temperaturen angehoben, so steigt die gesamte Entropieproduktionszahl stark an, wobei die Dissipation durch Fluidreibung nun die Hauptursache für die auftretenden Verluste in beiden Strukturen ist.

Shape Optimization of Heat Exchanger Fin Structures Using the Adjoint Method and Their Experimental Validation

“…The initial design for the optimizations presented in this paper is based on a parameter variation of different fin parameters (fin height, fin spacing, fin length and fin longitudinal displacement), which are presented in Fuchs et al [14]. The different fin parameters are evaluated on the basis of their entropy production number, and a parameter combination that has the lowest entropy generation is selected [15]. Based on this fin geometry, various optimizations for high heat transfer and low-pressure loss have been carried out by adjusting the fin shape to the corresponding thermal and hydrodynamic boundary layer.…”

Experimental Investigation of Additively Manufactured High-Temperature Heat Exchangers

“…The Nusselt-numbers can directly calculated by using the fluid and wall temperatures from the numerical calculations, using the definition of the logarithmic temperature difference for constant wall heat flux [29]. For more information on the numerical details of the fin type "Reference", such as validation against literature, determination of the Nusselt number, respectively j-and f-factors and mesh independence, please refer to Fuchs et al [19] and [30]. The fin types "FO" and "HTO" are based on the fin type "Reference", which is why the calculation mesh used there is used as a starting point and is refined using mesh independence analysis until a mesh-independent result is available.…”