# 2 phase flow density relationship

### Multiphase Flow Properties & Pressure Gradient Calculation - Production Technology

In fluid mechanics, two-phase flow is a flow of gas and liquid — a particular example of Similar differences are typical of water liquid/water vapor densities. flow · Buckley–Leverett equation · Darcy's law for multiphase flow (for flow through. Analysis of two phase flow systems is complicated by the appearance and . the liquid phase energy equation is .. + g g is the effective two-phase density ρ. In the next paragraphs, two-phase flow properties (holdup, densities, Then the pressure gradient equation which is applicable to any fluid.

Three equations for two-phase density are used by various investigators in two-phase flow: Calculation of the two-phase viscosity requires knowledge of the liquid holdup.

Two equations for two-phase viscosity are used by various investigators in two-phase flow: General Pressure Gradient Equation: This equation is usually adapted for two-phase flow by assuming that the two-phase flow regime and two-phase properties can be considered homogeneous over a finite volume of the pipe.

Many correlations have been developed for predicting two-phase flow pressure gradients which differ in the manner used to calculate the three terms of pressure gradients equation elevation change, friction, and acceleration terms: No slip, no flow regime considerations: No distinction is made for different flow regimes.

### Mixture Density - Two-phase Flow

Slip considered, no flow regime consideration: The same correlations for liquid holdup and friction factor are used for all flow regimes.

Slip considered, flow regime considered: Usually a different liquid holdup and friction factor prediction methods are required in each flow regimes.

Starting with the known inlet pressure and flow rates. Calculate the average pressure and, for non-isothermal cases, the average temperature in the increment. Determine the gas and liquid properties based on black-oil or compositional model at average pressure and temperature conditions.

### Slip ratio (gas–liquid flow) - Wikipedia

If they are not sufficiently close, estimate a new value and return to step 3. Repeat the steps 2 to 7 for the next pipe length increment. Flow Correlation Information Multi-phase flow correlations are used to predict the liquid holdup and frictional pressure gradient.

• Mixture Density – Two-phase Flow
• Slip ratio (gas–liquid flow)
• Multiphase Flow Properties & Pressure Gradient Calculation

If pressure drops further, which can happen locally near the vanes for the pump, for example, then a phase change can occur and gas will be present in the pump. Similar effects can also occur on marine propellors; wherever it occurs, it is a serious problem for designers. When the vapor bubble collapses, it can produce very large pressure spikes, which over time will cause damage on the propellor or turbine.

The above two-phase flow cases are for a single fluid occurring by itself as two different phases, such as steam and water. The term 'two-phase flow' is also applied to mixtures of different fluids having different phases, such as air and water, or oil and natural gas.

Sometimes even three-phase flow is considered, such as in oil and gas pipelines where there might be a significant fraction of solids. Although oil and water are not strictly distinct phases since they are both liquids they are sometimes considered as a two-phase flow; and the combination of oil, gas and water e. Other interesting areas where two-phase flow is studied includes in climate systems such as clouds[1] and in groundwater flow, in which the movement of water and air through the soil is studied.

Other examples of two-phase flow include bubblesrainwaves on the seafoamfountainsmoussecryogenicsand oil slicks. Characteristics of two-phase flow[ edit ] Several features make two-phase flow an interesting and challenging branch of fluid mechanics: Surface tension makes all dynamical problems nonlinear see Weber number.

Two-Phase flow

In the case of air and water at standard temperature and pressurethe density of the two phases differs by a factor of about The sound speed changes dramatically for materials undergoing phase change, and can be orders of magnitude different.