What are the most common and useful multiphase CFD applications and case studies?

CFD applications I have worked on include separators, flash columns and heat exchangers. It's important to remember that CFD should be designed to investigate something. Don't expect to run CFD and have answers. It's a tool, and must be used in the right way. Often, this can mean working in tandem with experimental results or with empirical or analytical models.

One application is the production of vapor from stored crude subjected to thermal and momentum boundary conditions. The effect of parameters such as flow rates, ambient and crude temperature, solar radiation, diffuser geometry and, fill level can be considered in such CFD application. Among the available approaches, namely, volume of fluid, mixture and, Eulerian-Eulerian approach- VOF with an appropriate phase change model is the suitable one for industrial applications primarily, due to lower computational cost. Ideally, Eulerian approach is the best, however, modelling individual species (with its transport equations) can become challenging and costly considering 10+ components in a crude.

Oil-Water Separation: Simulating the separation process in oil-water separators to optimize design and efficiency. Gas-Liquid Flows in Pipelines: Understanding flow patterns and optimizing transportation in pipelines containing both gas and liquid phases. Multiphase Flow in Reservoirs: Modeling fluid behavior in reservoirs to enhance oil recovery strategies.

I worked for GE oil and gas drilling tools where we used to find the effect of different sizes of sand particles on the erosion of tools using CFD Discrete phase modeling. It was interesting to predict the erosion pattern on different tools.

Common and Useful Multiphase CFD Applications: 1. Oil and Gas Extraction: Simulates fluid flow in reservoirs and pipelines. 2. Chemical Reactors: Optimizes mixing and reaction processes. 3. Environmental Studies: Predicts pollutant dispersion in air and water. e.g. Notable Case Studies ~ Bubble Dynamics: Analysis in flotation tanks. ~ Droplet Behavior: Study in spray systems. ~ Slurry Flows: Examination in pipeline transport.

Fluidized Bed Reactors: Studying the behavior of particles and gas in fluidized bed reactors for efficient chemical reactions. Spray and Atomization: Analyzing spray dynamics in various industrial processes like spray drying, fuel injection, or pharmaceutical manufacturing. Bubble Column Reactors: Investigating gas-liquid interactions in bubble column reactors for chemical processing.

Multiphase CFD has indeed played a pivotal role in improving the efficiency and sustainability of chemical and pharmaceutical manufacturing processes. The ability to accurately simulate and analyze complex interactions between different phases (gas, liquid, and solid) has allowed engineers to gain valuable insights and optimize various aspects of equipment design and operating conditions. In the case of fluidized bed reactors, multiphase CFD can help identify the ideal conditions for achieving uniform mixing, effective heat transfer, and optimal reaction rates. This can lead to significant improvements in product quality, yield, and process economics, as well as a reduction in greenhouse gas emissions and waste generation.

For example, In the design of an air conditioning system, it is important to ensure that the evaporator coil is operating efficiently and providing the desired cooling capacity. However, the presence of condensate on the coil surface can lead to a decrease in heat transfer and reduced system performance. To address this issue, multiphase CFD simulations can be used to study the flow and heat transfer characteristics of the air and water mixture in the evaporator. Similar CFD models typically include the simulation of the two-phase flow of air and water on the evaporator coil surface. The simulation accounts for the interaction between the two phases, as well as the heat transfer between the coil surface and the surrounding air.

Likely the most difficult cfd for compressors would be supercritical CO2 at, near and going through the dome. What would happen during surge?

Following the growth of hydrogen industry, the multiphase model is a must for electrolyser and fuel cell simulations. The two-phase fluid distribution plays a vital role in the overall cell performance. Multiphase models allow us to have in-depth assessment of the fuel cell or electrolyser design by understanding the correlation between the reactant/product distribution inside each cell component and the electrochemical output.

One application is the calibration of hydraulic relations for overflow monitoring. In a context of evaluation of spillage from a major combined sewer overflow, the continuous measurement of the discharged volume is needed. Using non contact water level measurement and CFD modelling of the water flows, it is possible to establish a site-specific head-discharge relationship, considering its geometry and hydraulic environment.

Sediment Transport: Simulating sediment transport in rivers or coastal areas to understand erosion or deposition processes. Pollutant Dispersion: Analyzing multiphase flows to model dispersion of pollutants in air or water bodies.

Drug Delivery Systems: Simulating the behavior of drug particles or droplets in inhalers, nebulizers, or drug delivery devices helps optimize particle size, distribution, and deposition in the lungs or targeted areas within the body. Blood Flow and Cardiovascular Modeling: Multiphase CFD is used to model blood flow in arteries, veins, and the heart. It aids in understanding the behavior of blood, including its interaction with vessel walls, the impact of different flow conditions on the cardiovascular system, and the design of medical devices like stents or artificial heart valves. Wound Healing and Drug Release. Tissue Engineering Pulmonary Function and Respiratory Modeling Bioreactors and Cell Culture

In automotive industry, multiphase modeling has been used conventionally to study vehicle soiling and water management studies. Multiphase CFD models are used to investigate how various driving circumstances, such as speed and wind direction, affect vehicle soiling. This information enables engineers to formulate methods that can reduce soiling in diverse operational situations. In water management, CFD multiphase modeling can be used to simulate vehicle passing through water puddles, rain impact and water collection by the wiper system, and investigate the impact on body of water on the powertrain components. Moreover, multiphase models are used to study sloshing inside fuel tank truck and coolant sloshing behavior inside reservoirs.

Food processing: Application: Mixing and separation processes in food manufacturing. Case Study: Centrifugal Separator in Dairy Industry CFD is employed to optimize the design of centrifugal separators used for separating cream from milk in dairy processing. Simulations help in understanding fluid-particle interactions, optimizing separator geometry, and enhancing separation efficiency while minimizing energy consumption.

Recently I have carried out a CFD anslysis for a water filter with a carbon block using VOF model where I had to show flow pattern within the filter with decreasing water level which helps to identify if the water is following a proper path within the system in order to get filtered properly from the carbon block. It was a very exciting project and very interesting transient analysis.