Computational Fluid Dynamics

Most processes in piping systems can be analyzed using a 1D flow model, due to the use of simple geometries, alongside previous comparisons of computed results to the vast amounts of available experimental data. However, some complex flow problems require a more in-depth analysis. When, for instance, either a complex geometry is used or multiphase flows are introduced, the 1D flow analysis does not provide sufficient detail to deliver accurate results. For analysis of these complex flow problems Computational Fluid Dynamics (CFD) is an essential tool.

What is a CFD analysis study?

Computational Fluid Dynamics (CFD) is a tool to analyze and solve problems that involve fluid flows. The fluid motion and heat transfer are solved using numerical schemes. CFD is applied to a wide range of research and engineering problems in many fields and industries.

Why perform a CFD analysis?

CFD provides a detailed description of the complex flow patterns and properties in the system. Due to the flexibility of the analysis, CFD has a wide range of applications. Moreover, due to recent advances in CFD, accurate predictions can be made to the flow properties of complex systems, such as pipe line component interferences, separation systems, or heat exchangers. This can be used to predict the performance of the analyzed system. Furthermore, CFD models are easily revised and can offer many detailed insights into the flow physics. Therefore, CFD can be used to replace expensive and time-consuming methods such as experiments, or for systems where no measurements are possible such as in deep sea applications or applications using liquid metal.

How are CFD analyses performed?

At Dynaflow Research Group we use Helyx-OpenFOAM for our CFD studies. HELYX is a comprehensive general-purpose CFD software package for engineering analysis and design optimization of enterprise applications, based on an advanced open-source simulation engine developed by ENGYS using OpenFOAM technology. The CFD simulation engine, HELYX, features an advanced hex-dominant automatic mesh algorithm with polyhedra support which can run in parallel to generate large computational grids. The solver technology is based on the standard finite-volume approach, covering a wide range of physical models.

After a thorough discussion with the client over the CFD analysis results; realistic mitigations will be proposed to improve the systems’ reliability, safety, and performance.

Multiphase flows

Systems containing multiple phases are difficult to capture in current 1D flow solvers, due to the three-dimensional nature of the flow. For these kinds of systems, CFD can help to provide an accurate insight into the fluid behavior. Dynaflow Research Group has performed numerous CFD analyses on multiphase flows. Our experience has been developed into a wide range expertise: different flow regimes, different geometry complexities, multiple flow scales, exotic, non-Newtonian fluids, dynamic geometries. We are confident in our ability to provide accurate results for any type of multiphase flow problem.

Design optimization of a slug catcher

In order to design a high performance ﬁnger-type slug catcher, it is necessary that the ﬂuid ﬂow in the inlet header manifold is evenly distributed among the diﬀerent ﬁngers. Diﬀerent conﬁgurations are deﬁned and compared using the time-averaged mass ﬂow at the ﬁnger inlets. The initial conﬁguration, leads to a large misdistribution in time-averaged mass ﬂow. Dynaﬂow performed an optimization study using CFD. Increased pipe diameter was found to promote the mass ﬂow balance. Additionally, by applying an extra split in the main header pipe, the equal ﬂow distribution was signiﬁcantly increased.

Particle-fluid interactions

There are many applications where the influence of particles in a flow cannot be neglected, such as dredging and certain types of food flow. In these cases, the interaction between the particles and the flow should be modelled in order to provide accurate results. Dynaflow Research Group has performed both small and large-scale analyses, with the implementation of particles within the flow.

HADES

The experience from these projects have led to the development of our own particle interaction solver called HADES, which can analyze the particle-fluid interaction of complex shapes and different particle sizes. With this solver and our experience in particle-fluid interaction analyses, we are able to provide an accurate representation of your system and help to find the solution to your specific problem.

Structural analysis in equipment

In some cases, performing only a CFD analysis is not sufficient in order to approve the design of a system or to find the root cause of a failure. Structural analysis can also be an integral part of the analysis. As Dynaflow Research Group is a multi-disciplinary engineering company, we can combine the results of a CFD analysis with a structural analysis.

Heat exchangers performance analysis

Heat exchangers are devices that facilitate the flow of thermal energy between two or more fluids at different temperatures. They are used in a wide variety of applications in the petrochemical industry. Dynaflow Research Group provides mechanical, thermal and flow analyses for all possible types of heat exchangers using the latest technologies and standards.

By providing realistic information regarding the flow pattern at every point in the system, CFD analyses are better able to predict all important heat transfer parameters as well as the heat transfer performance for arbitrary geometries and flow conditions. This is in contrast to the traditional method, which assumes uniform flow and requires conventional geometries. CFD calculations also provide vital information regarding the fluid forces acting on the system.

Optimization of in-line components

In-line components such as valves and orifices are key features of industrial installations. Using CFD the locations and design of these components can be optimized in order to mitigate possible failures or significant pressure drops due to hydrodynamic effects. At Dynaflow Research Group we combine our extensive experience in working with these in-line components with parametric CFD models in order to optimize the design of your in-line components such as the following.

Detailed Flow Analysis of a Butterfly Valve and Piping

The flow of water in a pipeline including a butterfly valve is analyzed. For unknown reasons, the installed valve was not able to fully open under operating conditions, with all pumps running. However, the valve fully opens when the system is not pressurized. Elbows were located close to both the upstream and downstream of the butterfly valve.

The objective of the study was to determine the relation between the opening of the valve and the dynamic torque acting on the valve, which is the torque exerted by the fluid. The computed torque versus opening diagram is then compared to the actuator capacity. For this reason, CFD analyses are performed for different angles. By inclusion of sufficient piping upstream and downstream of the elbows within the model, the effect of the elbows is taken into consideration. The CFD analysis performed on the valve under the specific operating conditions and the layout of the pipes has clearly shown that the torque acting on the valve remains within the permissible values.

Other applications

CFD analyses are not limited to the subjects discussed above. Many more applications are possible and are well represented in our project portfolio:

Heat transfer in burners,
Interference of pipe line components such as filters, valves pump inlet/outlet etc.,
Flow inside pumps and compressors.

What is possible with CFD?

The types of analyses that can be performed in a CFD application are:

Optimizing design to improve performance,
Validating initial design performance,
Determining cause of performance issues or failures,
Feasibility study of new configurations, e.g. closely spaced filters or pumps,
Fluid structure interaction analysis to solve the interaction of some movable or deformable structure with an internal or surrounding fluid flow.

About DRG

Dynaflow Research Group has years of experience in applying advanced CFD techniques. Many of our engineers have obtained an MSc or PhD using CFD and have obtained experience in using a variety of tools like OpenFOAM, HELYX, ANSYS Fluent and ANSYS CFX on a wide variety of projects. DRG is a respected partner to work with and to help you gaining a better understanding of the flow inside any equipment. So, if you are dealing with a complex flow problem or require a CFD analysis to validate your design, feel free to contact us.