Radial Diffusers – Simulation of Three‐Dimensional Flow Effects with CFD (Part 3)

Abstract

Radialdiffusoren dienen der Be-und Entladung von thermischen Speichern und beeinflussen signifikant die Ausbildung der thermischen Schichtung. Die Veröffentlichungsreihe behandelt dreidimensionale Strömungseffekte. Ü ber den Umfang des Radialdiffusorauslasses kann eine ungleich verteilte Ausströmung auftreten, die mit einer stärkeren Vermischung als bei einer rotationssymmetrischen Ausströmung bzw. Modellierung einhergeht. Der Beitrag diskutiert Maßnahmen zur Vermeidung dieses asymmetrischen Ausströmens.Radial diffusers are used for the loading and unloading of thermal energy storages and have a significant influence on the thermal stratification. Three-dimensional flow effects during the development of the thermal stratification in a hot water storage tank are discussed. An unequally distributed outflow was observed, which is accompanied by strong mixing. Possible solutions of this behavior are presented.

Assessment of Inlet Mixing During Charge and Discharge of a Large-Scale Water Pit Heat Storage

“…In this context, inlet/outlet diffusers with baffle plates [14][15][16][17][18] and porous manifolds inlets [19][20][21] have been successfully suggested. Radial diffusers have recently been studied in detail using Computational Fluid Dynamic (CFD) and experiments by Findeisen et al [22][23][24][25][26]. They emphasized that when there was a large distance between the diffuser and storage top wall, the stratification quality could be significantly reduced due to strong mixing.…”

Modeling a Large Thermal Energy Storage System Using RANS Turbulence Models and High-Resolution Measurement Data

“…Findeisen et al [9]- [11] studied the influence of diffuser design and operation on the flow and temperature distribution in the direct vicinity of the diffuser using high-resolution RANS turbulence models such as the SST-k-ω-model. They clearly demonstrated the need for turbulence modeling when analyzing TES of this type, most pressingly in the regions in and around the upper and lower radial diffusers.…”