GENERALIZATION OF AN ANALYTICAL TWO-PHASE STEAM FLOW CALCULATOR TO HIGH-PRESSURE CASES

2006 ◽  
Vol 30 (4) ◽  
pp. 581-595
Author(s):  
M. J. Kermani ◽  
M. Zayemouri ◽  
M. Saffar Avval
Keyword(s):  
High Pressure ◽  
Local Equilibrium ◽  
Low Pressure ◽  
Ideal Gas ◽  
Steam Flow ◽  
Stagnation Temperature ◽  
Two Phase ◽  
Dimensional Parameter ◽  
Phase Mixture ◽  
Experimental Values

Extension of a recently developed analytical two-phase steam flow calculator to high pressure cases is performed in this paper. The initial solution, obtained in earlier study was developed for low pressure cases. In low pressure cases, the vapor portion of the two-phase mixture reliably obeys the ideal gas Equation of State (EOS). In the present high pressure study, real gas effects are included using the more suitable EOS of “Lee-Kesler”. The model similar to the low pressure model assumes local equilibrium between the phases, in which condensation onsets as soon as the saturation line is closed. Before the condensation onset, the stagnation properties echo those at the inflow. However, beyond the condensation onset, the transfer of latent heat toward the vapor portion of the two-phase mixture rises its stagnation temperature. To evaluate this rise in the vapor portion stagnation temperature, a non dimensional parameter ζ is defined. Comparison for low- and high-pressure cases between the present analytical solution and the published experimental values in the literature show very good agreement.

Enhanced Low-Pressure Pneumatic Conveyance Using Swirl

2010 ◽  
Author(s):  
Rodrigo Escandon ◽  
Randall D. Manteufel ◽  
Q. Ken Su
Keyword(s):  
Vertical Section ◽  
Experimental System ◽  
Low Pressure ◽  
Phase System ◽  
Pneumatic Conveying ◽  
Two Phase ◽  
Before And After ◽  
Pneumatic Conveyance ◽  
Experimental Values

Two designs for swirl amplification have been considered for pneumatic conveyance in vertical pipes. Both designs have been experimentally evaluated in order to predict their capability. The designs have been compared to other methods of amplification or swirl generation. The motivation for the swirl in pneumatic conveyance is to minimize axial velocity by using multiple swirl amplifications to enhance the transportation for long distances. In this experimental evaluation two swirl amplifiers are considered. The evaluations are done by determining the static pressures before and after the swirl amplifier in the vertical section of an experimental system. This difference in pressure points allowed the determination of length of decay, which is the distance in which this two-phase system travels before a reduction in radial velocity. In the amplifiers, compressed air at two pressures was used for the purpose of creating a low pressure pneumatic conveying system. It is determined that when using these amplifications in the air boost, longer lengths of decay can be achieved in comparison to a no swirl system. This meant that the products transportation could be enhanced due to the addition of the swirl amplifiers. The experimental values were used to compare both designs. The more productive one was determined by its length of decay. As well as estimating the maximum obtainable distances for both swirl amplifiers at each particular amplification.

Application of Modified PANS Model for Computation of Cloud Cavitation around a Clark-Y Hydrofoil

2013 ◽  
Vol 456 ◽  
pp. 173-177
Author(s):  
Wei Dong Shi ◽  
Guang Jian Zhang
Keyword(s):  
Turbulent Viscosity ◽  
Lift Coefficient ◽  
Correction Function ◽  
Navier Stokes ◽  
Two Phase ◽  
Cloud Cavitation ◽  
Cavity Shedding ◽  
Time Average ◽  
Phase Mixture ◽  
Experimental Values

A density correction function was introduced to the Partially-Averaged Navier-Stokes Model (PANS) taking into account the local compressibility of two-phase mixture. The standard k-ε model, PANS model and the modified PANS model were used to simulate the unsteady cloud cavitation around a Clark-y hydrofoil and the evolutions of cavity shape, time-averaged turbulence viscosity distribution and lift coefficient variation were investigated. The results compared with experimental data show that the PANS model and the modified PANS model strongly reduce the turbulent viscosity and predict the cloud cavity shedding behavior observed in the experiment successfully, while the cavitation area and time-average lift coefficient predicted by the modified PANS model is closer to the experimental values than the original PANS model.

Two-Phase Eulerian/Lagrangian Model for Nucleating Steam Flow

2002 ◽  
Vol 124 (2) ◽  
pp. 465-475 ◽  
Author(s):  
A. G. Gerber
Keyword(s):  
Three Dimensional ◽  
Low Pressure ◽  
Steam Flow ◽  
Nucleation Theory ◽  
Lagrangian Model ◽  
Classical Nucleation Theory ◽  
Navier Stokes ◽  
Steam Turbines ◽  
Complex Flow ◽  
Two Phase

This paper describes an Eulerian/Lagrangian two-phase model for nucleating steam based on classical nucleation theory. The model provides an approach for including spontaneous homogeneous nucleation within a full Navier-Stokes solution scheme where the interaction between the liquid and gas phases for a pure fluid is through appropriately modeled source terms. The method allows for the straightforward inclusion of droplet heat, mass, and momentum transfer models along with nucleation within complex flow systems as found, for example, in low pressure steam turbines. The present paper describes the solution method, emphasizing that the important features of nucleating steam flow are retained through comparison with well-established 1-D solutions for Laval nozzle flows. Results for a two-dimensional cascade blade and three-dimensional low pressure turbine stage are also described.

scholarly journals Modernization of Two-Phase Oil and Gas Separator

2020 ◽  
Vol 33 (02) ◽  
pp. 616-622
Author(s):  
Guzel Rafikovna Ganieva ◽  
Putu Aunda Niradgnani
Keyword(s):  
High Pressure ◽  
Gas Separation ◽  
Oil And Gas ◽  
Raw Materials ◽  
Low Pressure ◽  
Technological Scheme ◽  
Operating Costs ◽  
Two Phase ◽  
Oil Separation ◽  
Gas Separator

Separators play an important role in the basis of the technological scheme and field preparation of oil and gas. Separation is the process of oil separation from gas. Depending on the requirements for the feedstock, separators are distinguished according to the principle of operation and purpose. In this paper, the company "PT Pertamina EP Asset 3 Subang", Indonesia (Nirajani) is considered as an example. Dimensions, efficiency, reliability of equipment, capital and operating costs are the main indicators of separator work and productivity. "Subang PT Pertamina EP Asset 3 Subang" collection station has 3 horizontal two-phase separators (high pressure, low pressure and test separator). In 2020, it is planned to increase the extraction of raw materials. In this regard, the aim of this work is to modernize the existing two-phase horizontal separator operated at the field. To achieve this goal, it is necessary to study the design of the existing separator, and calculate its performance (Nirajani). After all the calculations, it is necessary to choose a separator suitable for performance. Modernization of the existing separator is economically feasible for this enterprise.

Investigation of Geometry, Total Condition and Waves Effect on Two Phase Liquid-Vapor Flow Using Equilibrium Thermodynamics

2012 ◽  
Author(s):  
H. Beheshti Amiri ◽  
A. A. Piroozi ◽  
S. Hamidi ◽  
M. J. Kermani
Keyword(s):  
Steam Turbine ◽  
Turbine Blade ◽  
Ideal Gas ◽  
Steam Flow ◽  
Vapor Flow ◽  
Equilibrium Thermodynamics ◽  
Two Phase ◽  
Expansion Fan ◽  
Steam Turbine Blade ◽  
Flow Through

In this paper, a numerical method is presented to solve the two-dimensional two-phase steam flow over a series of geometries (such as nozzles, expansion corners and steam turbine blade-to-blade passages) by means of equilibrium thermodynamics model. The flow is assumed to be compressible and inviscid and obeys the ideal gas equation of state. The resulted equations are then numerically solved by the Roe’s FDS time marching scheme that has recently been modified to allow for two-phase effects. Validations of condensing steam flow through vapor nozzles have been performed, where good agreement has been achieved. Detailed parametric studies monitoring the influence of (I) the geometry expansion rate, (II) the inlet total temperature and pressure, and (III) the expansion fan or shock waves on the location of condensation onset and the rate of condensation are given. Finally as a case study, expansion of steam flow through a steam turbine blade-to-blade passage is considered, and condensation or evaporation of the steam flow through the passage and fate of the wet flow through the fan or shocks were observed.

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