A macroscopic particle modelling approach for non-isothermal solid-gas and solid-liquid flows through porous media

Abstract

The complexity of multiphase flows in many engineering systems such as heat exchangers signify the need to develop new and advanced numerical models to analyse the interactions the working fluid and unwanted solid foulants. Fouling is present in a myriad of industrial and domestic processes and it has a negative impact on the economy and the environment. The mechanisms that govern non-isothermal solid-fluid flow through porous metal foam heat exchangers are complex and poorly understood. In this research, a coupled finite volume method (FVM) and macroscopic particle model (MPM) is developed and implemented in ANSYS Fluent to examine the transient evolution of a non-isothermal multiphase solid-fluid flow and the interaction between coupled interactions of solid particles, fluid, and porous media. The maximum particle temperature is dependent on the fluid and solid particle thermo-physical properties in addition to the temperature of the cylindrical ligaments of the porous media. The present results show that the smallest solid particles reach the highest temperatures in the porous heat exchanger and at low inlet velocities, the highest particle temperatures are realized. The results pertaining to maximum particle temperatures are prevalent in many industrial processes and acquiring knowledge of the maximum particle temperature serves as a steppingstone for comprehending complex multiphase solid-fluid flows such as the cohesiveness between the particles and the particle adhesion with the walls. The results of these studies could potentially be used in the future to optimize metal foam heat exchanger designs.

Heat-exchange units with porous inserts

“…The experimental results made it possible to analyze the degree of water cooling for various periods of time using a material with a different coefficient of porosity. Figure 4 presents the experimental results, which almost coincide with the results of calculations using formulas (2)- (5). This high accuracy of calculations is partially explained by the fact that the boundary conditions are taken from the same experiments.…”

“…The housing cross section is cylindrical round or oval. [4][5][6][7][8] There are original designs of evaporation elements, which are intended to cool bodies in various fields of industry. The evaporation element is made in a form of a three-layer wall adjacent to the heat transfer surface with boundary and middle layers having various porosities.…”

Analysis of the Efficiency of Using Heat Exchangers with Porous Inserts in Heat and Gas Supply Systems

“…The first circuit with water was equipped with pump (4), boiler (5) for heating water, and control and measuring device (6), which makes it possible to track the change in water temperature over time and monitor the mass flow rate. The freon circuit is created using the principle of a refrigeration unit and is equipped with compressor (7), condenser (8), receiver (9), a moisture-separating filter, (10) and a throttle (12). In addition, the freon circuit (Figure 1) was equipped with devices for measuring temperature and freon pressure at the inlet and outlet to the compressor and flow meter (11).…”

“…The choice of porous metals for the designs of heat exchangers depends on their application [12,13]. For example, porous metals are used in cooling systems for rocket engines, as well as in the chemical and petrochemical industries [14][15][16].…”

The use of porous metals in the design of heat exchangers to increase the intensity of heat exchange

“…Their heat transfer process is well-known, and it is difficult to obtain significant increase in the heat transfer coefficient. Recently, the problem of designing new heat exchangers (for example with porous metals) has become urgent [1][2][3][4][5][6][7][8].…”