In this research the one dimensional TWO-PHASE FLOW equqtion for the simultaneous FLOW of air and water from a vertical soil column presented here based on the aljebraic sum of the water and air velocities (the total velocity) which have been derived elsewhere .In evaluating some of hydraulic parameters, the Brooks - Corey functions (Brooks and Corey 1964) are used. For the relative permeability and effective saturated to wetting and no wetting PHASEs are used to calculated the parameters in this equation.To obtain hydraulic parameters in the Brooks and Corey equation, experimental investigation presented and hydraulic conductivity is measured and the same column homogeneous soil is dryed.The experimental data is companied with the predicted values by this equation, which was showed a good agreement.On the other hand the values of D* and a are culculated by the Brooks - Corey functions and the results of the changes of these parameters over the conclusions were evaluated and it shoued that the D* changes had a significant or meaningful effect on the computations but the changes of a had not a considerable effect on the computations so, we can consider its quantity as (1) because its practical objects. Concerning to the complicated connection of quantities the volume of computations is reduced considerably.

Different measures may be taken into account in order to reduce the destructive effects of FLOW over spillways, one of which is the application of stepped spillways in an attempt to dissipate the FLOW energy. This method also influences the economic justification of the project and reduces the costs. The present study simulated the free surface and the TWO-PHASE FLOW patterns over the stepped spillway employing the Fluent software, and adopting the mixture model as well as the standard K - E turbulence model. The numerical model verification was conducted utilizing the data of air concentration distribution in water, and the velocity at different discharge rates collected in experiments performed by Chamani utilizing a physical model at Hydraulic Laboratory conducted at the University of Alberta. The numerical simulation results and experimental data were in good agreement. Concentration profiles led to a stair like distribution of the concentration, and the discharge effects on the shapes of velocity profiles were comparable. The results showed that as the inlet discharge increased, velocity profiles widened and spread more, and FLOW height and maximum FLOW velocity rose, which in turn reduced the FLOW dissipation.

Continuous gas lift process is used to boost oil production in many mature reservoirs, which can no longer produce under natural drive. In this article, application of mechanistic FLOW maps as well as the correlations estimating pressure drop in a gas lifted well, as the most complex and time consuming part of the gas lift modeling is examined. Using the black-oil model to compute the TWO-PHASE pressure drop in a gas lifted well leads to a substantial error due to the changes in composition and bubble point pressure along the well. In order to describe the thermodynamic behavior of the hydrocarbon fluid, a multicomponent compositional description has been applied using the reduced parameter method. The results show that the empirical maps and correlations lead to severe discontinuities at transition points between the different FLOW regimes. This causes an unacceptable error when computing the pressure drop.

In TWO PHASE FLOW investigation, there is a need for robust methods capable of predicting interfaces, in addition to treating the traditional governing equations of fluid mechanics (Navier-Stokes Eqs). Such methods in a finite volume approach can be classified into TWO typical categories called interface tracking and interface capturing methods. According to their abilities, interface capturing methods are of more interest in free surface modeling, especially when complex interface topologies such as wave breaking are included. These methods solve a scalar transport equation in order to find the distribution of TWO PHASEs all over the computational domain. That is, all properties of the effective fluid will be calculated. In this paper, some existing schemes will be reviewed and TWO high order composite schemes will be applied on a discretised form of the volume fraction convection equation. A discussion on the performance of methods will be presented as a result of different scalar distribution convection in various velocity fields according to the program that has been developed in this manner. It will be presented to show that CICSAM (Compressive Interface Capturing Scheme for Arbitrary Mesh) can be used as a good choice for free surface simulation in practice.

The paper presents the modeling of TWO-PHASE FLOW in turbulent FLOW. For this purpose, a TWO-fluid turbulence model is used. The work can be considered the development of a TWO-fluid approach to the problem of turbulence, which, unlike Reynolds' approach, leads to a closed system of equations. Therefore, the system of equations for a TWO-PHASE FLOW given in the work based on the TWO-fluid approach is also closed and no additional hypotheses are required. The resulting system of equations for a turbulent TWO-PHASE FLOW is implemented numerically for a TWO-PHASE FLOW in a cylindrical pipe and in a free jet. The obtained results are compared with known experimental data, as well as with the results of the Reynolds stress method (RSM). The results of the proposed model are in good agreement with experimental data. In addition, it is shown that the model adequately describes the phenomenon of “turbulent migration of particles, ” resulting in the accumulation of inertial particles on the axis and wall of the pipe.

Applications of TWO-PHASE FLOW in nuclear power plants, transmission lines, oil and gas have been considered in recent decades. Different models have been introduced that can contribute to the current TWO-PHASE FLOW approach to numerical analysis. TWO-fluid model is the most widely used and most accurate model for predicting TWO-PHASE FLOW in channels during different regimes of unstable FLOW. This study addressed the PFM model Hyperbolicity. Hyperbolicity of this model is the most important for the well-posed condition, otherwise the model isinill-posed condition and the results are unstable numerically. Hydrodynamic instability of TWO-PHASE gas-liquid by using the PFM model is calculated and discussed.

Although TWO-PHASE FLOW is frequently encountered in various locations of the process plants, there is no a generally accepted and verified TWOPHASE FLOW model that may be used to size lines for such conditions. An obvious example is condensate water return lines. The API method used in this study is based on the homogeneous equilibrium FLOW assumption, that is, equal velocity and equal temperature in both liquid and vapor PHASEs. Moreover, DIERS method was used to verify and clarify the HEM approach to calculating the pressure drop in TWOPHASE regimes. The objective of this study is to introduce a solution for process lines design during different flashing scenarios. Applying API method, this study can find the TWO-PHASE line pressure drop and upstream pressure, while, by using DIERS method, one could realize that for a specified length of pipe how much TWO-PHASE FLOW could pass through when the pressure drop is just the same as that in the API model.