Computational Fluid Dynamics Modeling of Gas-Particle Flow Within a Solid-Particle Solar Receiver

Abstract

A detailed three-dimensional computational fluid dynamics (CFD) analysis on gas-particle flow and heat transfer inside a solid-particle solar receiver, which utilizes free-falling particles for direct absorption of concentrated solar radiation, is presented. The two-way coupled Euler-Lagrange method is implemented and includes the exchange of heat and momentum between the gas phase and solid particles. A two-band discrete ordinate method is included to investigate radiation heat transfer within the particle cloud and between the cloud and the internal surfaces of the receiver. The direct illumination energy source that results from incident solar radiation was predicted by a solar load model using a solar ray-tracing algorithm. Two kinds of solid-particle receivers, each having a different exit condition for the solid particles, are modeled to evaluate the thermal performance of the receiver. Parametric studies, where the particle size and mass flow rate are varied, are made to determine the optimal operating conditions. The results also include detailed information for the gas velocity, temperature, particle solid volume fraction, particle outlet temperature, and cavity efficiency.

Thermal Performance Evaluation of Two Thermal Energy Storage Tank Design Concepts for Use with a Solid Particle Receiver-Based Solar Power Tower

“…Chen et al [15] developed a 3D CFD model to study the influence of particle size and other operating conditions on the performance of solid particle receivers. Researchers at Aachen University and the German Aerospace Centre (DLR) introduced the concept of storing energy in quartz sand as a part of their work on air volumetric receivers [16,17].…”

“…One variation of this system is shown in Figure 1, which includes a general view of the tower and the heliostat field and a detailed view of the central receiver concept. This work builds on the experience of other developers using sand as the proposed storage medium in trough plants, as well as the work of other investigators, such as work on the SPR concept that was introduced and tested at the National Solar Thermal Test Facility in SNL [15,22]. The proposed system is expected to overcome the issue of low solar energy absorption efficiency through the use of a novel cavity receiver design that has been tested at Sandia's solar facility.…”

Modelling of solar thermochemical reaction systems

“…The MC method very naturally includes arbitrarily complicated spectral behaviour and many of the references using MC listed above include it. Less precise approximations such as the band approximation with two bands have appeared (Chen et al, 2007;Haussener et al, 2009) as well as studies that ignore spectral dependence entirely-the grey approximation (Abanades et al, 2007;Groehn et al, 2016;Wang et al, 2014a,b). The radiative properties of gases have dramatic spectral variation, particularly at the high temperatures achieved in STRSs and may lead to vastly different results (Modest, 2013).…”

“…The DO is a discretisation approach that relies on replacing the specific intensity, which is continuous in propagation direction, with a finite number of specific intensities evaluated at certain propagation directions (abscissa), thus forming a quadrature for properties calculated by integrals over direction-internal energy density, heat flux, etc. It has appeared in several studies, likely because of its availability in the popular simulation package from ANSYS (Abanades et al, 2007;Chen et al, 2007;Haussener et al, 2009). The zonal method-a method relying on finite volumes (zones) and the concept of exchange areas-is used in (Oles and Jackson, 2015;.…”

“…Falling particle receivers fall into the category of dilute fluidised STRSs because it can be approximated that the particles do not directly interact with each other. However, gas entrainment is an important phenomenon in these systems as was accounted for in (Oles and Jackson, 2015) by using a semiphenomenological approach and more rigorously in (Chen et al, 2007) for non-reactive particles. The works discussed thus far consider flows with Reynolds numbers that are-or are assumed-low enough that laminar flow modelling is sufficient.…”