Basics of Two Phase Modeling in FlowNex

Unlock the secrets of efficient fluid dynamics with two-phase modeling in FlowNex, revolutionizing the manufacturing industry.

Challenges

Two-phase flow refers to the simultaneous flow of two distinct phases, typically liquid and gas, which have different properties and behaviors. In the manufacturing industry, understanding two-phase flow is crucial for optimizing processes such as heat exchangers, chemical reactors, and fluid transport systems.

By accurately modeling two-phase flow, engineers can predict and control the behavior of fluids under various conditions, leading to improved efficiency and reduced operational risks.

Challenges in two-phase modeling include handling the non-linear interactions between phases, dealing with phase change phenomena, managing complex geometries and varying operational conditions, and ensuring numerical stability during simulations.

These challenges require a deep understanding of fluid dynamics and the use of sophisticated modeling techniques to overcome them effectively.

Engineering Solution

FlowNex provides a robust platform for modeling two-phase flow, offering significant benefits for the manufacturing industry. It enables precise simulations that help in designing more efficient systems and reducing trial-and-error in prototyping.

By using FlowNex for two-phase modeling, manufacturers can achieve better control over their processes, leading to cost savings, enhanced safety, and improved product quality.

Engineering solutions for two-phase modeling involve the use of advanced simulation software like FlowNex, which provides the necessary tools and features to model complex two-phase flows accurately.

Collaboration between engineers and software experts is crucial to customize the models according to specific manufacturing needs and achieve optimal results.

FlowNex works with piece-by-piece network building philosophy which provides an easy visual representation of the system that user works on.

The two-phase fluids are mostly used in Rankine conversion cycles. Figure 1 demonstrates a schematic representation of a Rankine cycle (left), and FlowNex application (right).

Figure 1. Schematic representation of a Rankine cycle (left), and a FlowNex application (right)

There are few underlying assumptions in FlowNex two-phase modeling:

Saturated liquid and vapor phases homogeneously mixed (no differentiation in location of individual phases during flow)
Thermophysical properties expressed as single values in weighted average combination
Mass, momentum or energy transfer between phases are not considered
Empirical correlations were utilized for friction factor and heat transfer during various boiling/condensation regimes
Critical flow models were applied for critical velocity and mass flux (choking)

The benefits of homogenous equilibrium model include reduced calculation complexity, speeded up solution time, and being conceptually more user friendly.

Some of the best practices of the two-phase modeling setup in Flownex can be summarized as:

Set the pressure relaxation parameter to 0.5 (to account for the large changes)
It is highly advised to specify the boundary values for quality as well as pressure or temperature until the network is balanced. Then the boundary values could be removed if necessary
For the pumps, use "specify level" instead of calculate level in steady-state level option panel. This will provide an option to add the boundary conditions in the same panel, as opposed to a generated boundary value in the network
Use two pressure boundaries (aids for convergence)
Assign sufficient increments to pipes for grid convergence

Confirm the convergence accuracy influence is efficient for the modeling purposes
Use a "Composite Heat Transfer" element than the one of the heat exchanger elements in order to capture the localized heat transfer effects

Ansys Solution Benefits

Ansys offers comprehensive solutions for two-phase modeling, providing powerful simulation capabilities and user-friendly interfaces. Its integration with FlowNex enhances the modeling process, allowing for more detailed and accurate simulations.

Using Ansys solutions, manufacturers can achieve faster time-to-market, reduced development costs, and improved product performance.

Ozen Engineering Expertise

Ozen Engineering Inc. leverages its extensive consulting expertise in CFD, FEA, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, addressing complex challenges like multiphase flows, erosion modeling, and channel flows using Ansys software.

We offer support, mentoring, and consulting services to enhance the performance and reliability of your particle flow system. Trust our proven track record to accelerate projects, optimize performance, and deliver high-quality, cost-effective results for both new and existing systems. For more information, please visit https://ozeninc.com.

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Tags:

Flownex, Two-phase Modeling

Post by Ertan Taskin
December 6, 2024