What is the ring flow?

Ring flow is a method of liquid and gas flow in the pipeline, where the material of the lighter molecular weight flows through the center of the pipeline and the heavier material of the molecular weight is made up of a thin film that flows along the pipe wall. It is often seen in the oil industry, where the flow rates are high and may occur in both horizontal and vertical tubes. Lighter mass fluid or gas can also be in the form of fog or colloidal suspension known as emulsion. The interface between the flowing materials may not be accurate and may include gas and liquid mixtures. In the wise ring flow, as the flow increases, the colloidal suspension of gas globules in the core increases and leads to the spread of globules into grim strips and lumps. There are also several other types of flow modes, including the flow of bubbles, slugs and outflows in the vertical pipe, as well as stratified and stratified waves in horizontal pipes.

Calculation of ring flows can be difficult because equations require an accurate level of inner pipe diameter. This is changing, because the annular flow has a non -flow limit inside, which changes the effective diameter of the pipeline. Precise values ​​are difficult to come depending on the calculation method used.

Two rows of equations are commonly used to determine the ring flow. The first is known as a wet perimeter flow, where the pipe diameter is divided by a square product of internal and external areas of the flow. The calculations of the wetted circuit are not ideal because they are based solely on the fact that the internal flow is deducted from the outer reaches without a contribution for an area without flow. The oil engineering method uses a more complicated method of comparing the internal and external flow and is known to cause the results of the flow is about 40% higher than the method of moistened circuit. It seems that oil engineering equations reflect the real measured flow better than the wet circuit method, but wet is the standard used in academic engineering.

Factors of friction must also be taken into account in the ring flow. The use of the outer surface of the pipeline to estimate friction is one method. It is also performed by the creation of an average friction based on weighted data and is considered legitimate approaches.

There are also different phases of gas flow-capalin in the pipeline, where transitions between different types of flow modes occur. Transitions may include shifts from ring to wise anular and connect to the ring flow in the vertical pipe. In the horizontal pipeline, conventional transitions include slugs to the ring crossing. These, like many other types of flow states and transitions, have all the unique mathematical models for calculating what the current flow is in the pipe.