Two-Phase Flow Field Characteristics Analysis on Seal Cavity for Bellows Mechanical Seal under Variable Operating Conditions

2012 ◽  
Vol 522 ◽  
pp. 436-440
Author(s):  
Li Chao Ren ◽  
Mutellip Ahmat ◽  
Qiang Gao ◽  
Jing Luo
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Optimization Design ◽  
Operating Conditions ◽  
Mechanical Seal ◽  
Two Phase ◽  
Cooling Effects ◽  
Two Phases ◽  
Two Phases Flow ◽  
Vapor Liquid

This research based on the vapor-liquid two-phases flow theory and methods, by using the CFD mix-multiphase flow model, the seal cavity vapor-liquid two-phases flow field for the bellows cartridge mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions was numerically simulated and analyzed, then the characteristics of the complex three-dimensional flow field of seal cavity caused by the rotation of the sealing ring were obtained by the different position of the injected coolant, and the different cooling effects were contrasted, then the best cooling position were found by analysis. The researching results provide a theoretical basis for the structural optimization design of the high parameters bellows cartridge mechanical seal devices.

An Impact of Self-Recirculation Casing Treatment (SRCT) Configurations on Impeller Stall Margin and the Flow Field

2012 ◽  
Author(s):  
Yan Ma ◽  
Guang Xi ◽  
Guangkuan Wu
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Operating Conditions ◽  
Centrifugal Impeller ◽  
Flow Angle ◽  
Stall Margin ◽  
Casing Treatment ◽  
Swirl Velocity ◽  
Inlet Swirl ◽  
Unsteady Simulation

The present paper describes an investigation of stall margin enhancement and a detailed analysis of the impeller flow field due to self-recirculation casing treatment (SRCT) configuration of a high-speed small-size centrifugal impeller. The influence of different SRCT configurations on the impeller flow field at near-stall condition has been analyzed, highlighting the improvement in stall flow ability. This paper also discusses the influence of the SRCT configurations on the inlet flow angle, inlet swirl velocity and loss distribution in the impeller passage to understand the mechanism of the SRCT configurations in enhancing the stall margin of the impeller. The variation of the bleed flow rate at different operating conditions is also presented in this paper. Finally, the time-averaged unsteady simulation results at near-stall point are presented and compared with steady-state solutions.

Numerical Simulation and Analysis of Effect of Injection Volume on Biomass Particle Cyclone Venturi Dryer

2021 ◽  
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Zicheng Gao ◽  
Dan Huang ◽  
Wei Li ◽  
...  
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Gas Flow ◽  
Continuous Phase ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Two Phase ◽  
Velocity Change ◽  
Injection Volume ◽  
Wood Debris

Abstract Cyclone venturi dryer is suitable for drying materials with large particle size and wide distribution. The working process of cyclone venturi dryer is a very complicated three-dimensional and turbulent motion, so it is difficult to be studied theoretically and experimentally. In order to study the internal flow characteristics of the biomass particle cyclone venturi dryer, the computational fluid dynamics (CFD) software was used to simulate the gas-solid two-phase flow field inside the cyclone venturi dryer. The continuous phase adopts the Realizable k-ε turbulence model and the particle phase is discrete. The effects of different injection volume on the pressure, velocity, and temperature fields inside a cyclone venturi dryer were analyzed. The results showed that the maximum pressure drop and velocity change inside the dryer were at the venturi pipe. The wet material of the cyclone venturi dryer was inhaled into the venturi contraction tube by the negative pressure formed after the highspeed airflow was ejected, thus the mixture was completed in the venturi throat. The wood debris material was mixed with the high-speed hot gas flow in the venturi throat and then sprayed into the diffusion pipe. In the diffusion pipe of venturi, the heat and mass transfer process of wet wood debris and heat flow in venturi diffusion tube was completed. It is in good agreement with the simulation results. This study can provide a reference for the optimization design of the related cyclone venturi dryer structure.

Visualization of Supercritical Carbon Dioxide Flow Through a Converging-Diverging Nozzle

2019 ◽  
Author(s):  
Chang Hyeon Lim ◽  
Gokul Pathikonda ◽  
Sandeep Pidaparti ◽  
Devesh Ranjan
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Critical Point ◽  
High Speed ◽  
Operating Conditions ◽  
Higher Plant ◽  
Two Phase ◽  
Pressure Profiles ◽  
Flow Through ◽  
Supercritical Carbon

Abstract Supercritical carbon dioxide (sCO2) power cycles have the potential to offer a higher plant efficiency than the traditional Rankine superheated/supercritical steam cycle or Helium Brayton cycles. The most attractive characteristic of sCO2 is that the fluid density is high near the critical point, allowing compressors to consume less power than conventional gas Brayton cycles and maintain a smaller turbomachinery size. Despite these advantages, there still exist unsolved challenges in design and operation of sCO2 compressors near the critical point. Drastic changes in fluid properties near the critical point and the high compressibility of the fluid pose several challenges. Operating a sCO2 compressor near the critical point has potential to produce two phase flow, which can be detrimental to turbomachinery performance. To mimic the expanding regions of compressor blades, flow through a converging-diverging nozzle is investigated. Pressure profiles along the nozzle are recorded and presented for operating conditions near the critical point. Using high speed shadowgraph images, onset and growth of condensation is captured along the nozzle. Pressure profiles were calculated using a one-dimensional homogeneous equilibrium model and compared with experimental data.

Numerical model of two-phase mechanical face seal with shallow grooves based on finite volume method

2020 ◽  
Vol 72 (10) ◽  
pp. 1303-1309
Author(s):  
Wenbin Gao ◽  
Weifeng Huang ◽  
Tao Wang ◽  
Ying Liu ◽  
Zhihao Wang ◽  
...  
Keyword(s):  
Flow Field ◽  
Phase Change ◽  
Finite Volume Method ◽  
Peer Review ◽  
Finite Volume ◽  
Fluid Model ◽  
Mechanical Seal ◽  
Two Phase ◽  
Content Type ◽  
Volume Method

Purpose By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, an effective method to study the flow field of the mechanical seal when both cavitation and boiling exist simultaneously is found. Design/methodology/approach Based on the finite volume method, a fluid model was developed to investigate a two-phase mechanical seal. The validity of the proposed model was verified by comparing with some classical models. Findings By modeling and analyzing the two-phase mechanical seal of the fan-shaped groove end face, which is prone to phase change, the analysis of the gap flow field of the mechanical seal was realized when cavitation and boiling existed simultaneously. Originality/value Based on the model proposed for different conditions, the pressure and phase states in the shallow groove sealing gap were compared. The phase change rate between the mechanical seal faces was also investigated. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2019-0537/

Development of the Change-Resisting Mechanical Seal in Changing Condition

2002 ◽  
Author(s):  
Liu Lu ◽  
Shenqi Ying
Keyword(s):  
Mechanical Seal ◽  
Work Condition ◽  
Two Phases ◽  
Vapor Liquid

Based on the experiment of the motion of mechanical seal face in changing work condition, the change of the phase-changing radius in mechanical seal in changing work condition is discussed. And the method to deal with the unstable mechanical seal caused by the change of the radius is shown. Based on the mechanical seal theory on vapor-liquid two phases in changing condition, the change-resisting mechanical seal is developed, which is applied to industry successfully.

Computational Investigation of the Flow Field Inside an Submersible Tubular Pump

2011 ◽  
Author(s):  
Yan Jin ◽  
Chao Liu ◽  
Jiren Zhou ◽  
Fangping Tang
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Optimization Design ◽  
High Efficiency ◽  
Simple Algorithm ◽  
Operating Conditions ◽  
Rotating Speed ◽  
Pumping System ◽  
Wide Range ◽  
Engineering Costs

Submersible tubular pump is particularly suitable for ultra-low head (net head less than 2 m) pumping station which can reduce the excavation depth, lower engine room height, simplify hydraulic structure, and save civil engineering costs. Submersible tubular pump with smaller motor unit can reduce the flow resistance. The flow field inside the submersible tubular pump is simulated in a commercial computation fluid dynamics (CFD) code FLUENT. The RNG k-ε turbulent model and SIMPLE algorithm are applied to analyze the full passage of a submersible tubular pump, the performance of pump such as head, shaft power and efficiency are predicted based on the calculation of different operating conditions. The simulations are carried out over a wide range of operating points, from 0.8 of the reference mass flow rate at the best efficiency point (BEP) to the 1.28 of the BEP flow rate at the same rotating speed. For verifying the accuracy and reliability of the calculation results, a model test is conducted. The comparison of simulation results and the experiment data show that the calculation performances are agree with the experiment results in the high efficiency area and large discharge condition, but in the condition of low discharge, it exists deviations between the two results. Compare with the numerical simulation and experiment, which can provide more evidences for the hydraulic performance prediction and optimization design of submersible tubular pump pumping system.

Experimental Characterization of the Flow Instabilities of a Mixed-Flow Multiphase Pump Operating Air and Water Through Local Visualization and Analysis of Dynamic Measurements

2015 ◽  
Author(s):  
Alberto Serena ◽  
Lars E. Bakken
Keyword(s):  
High Speed ◽  
Numerical Models ◽  
Operating Conditions ◽  
Test Facility ◽  
Two Phase ◽  
Flow Mechanisms ◽  
Local Measurements ◽  
Specific Geometry ◽  
Promising Development

Part load operation of pumps generates flow and machine instabilities, which are not desirable and should be avoided as they result in premature wear and mechanical problems. Two-phase flow introduces additional challenges, both at the design and operational stages, due to the different phase behavior and mutual interaction. The phenomena involved present an intermittent character and are strongly dependent on the specific geometry and operating conditions. Despite the recent promising development of numerical simulations capabilities, an accurate characterization of the flow mechanisms still relies on real tests, which are needed to validate the numerical models too. An advanced laboratory test facility built at the Norwegian University of Science and Technology provides the required optical access to the pump channels, and high-speed recordings, along with local measurements of the pressure pulsations, allow to describe the flow structures in terms of location, length and time scales, and relate them to overall machine measurements, such as flow, pressure and torque. This provides a wide collection of test data of great value for a further understanding of the surging phenomenon, the development of a surging onset prediction model and a control strategy. Tests are performed covering the whole range of flow rates; a characteristic surging condition is identified and described in the article.

A Pressure-Base One-Fluid Compressible Formulation for High Speed Two-Phase Flows With Heat and Mass Transfer

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Yan Luo ◽  
Jianqiu Zhou ◽  
Xia Yang ◽  
Zhanxiang Jiang
Keyword(s):  
Numerical Method ◽  
High Speed ◽  
Immiscible Fluids ◽  
Numerical Results ◽  
Cavitating Flows ◽  
Two Phase Flows ◽  
Two Phase ◽  
Two Phases ◽  
Locally Homogeneous ◽  
Homogeneous Media

This paper presents a numerical method for high-speed compressible cavitating flows. The method is derived from one-fluid formulation in a sense that the two phases are well mixed and the mixture is considered as a locally homogeneous media. Energy equation is solved to predict the temperature evolution which is then used together with pressure to update the density field. A volume of fluid (VOF) phase-fraction based interface capturing approach is used to capture the phase front between the two immiscible fluids. The derived formulations have been implemented into a pressure-based, segregated algebraic semi-implicit compressible solver in Openfoam, which can be used to solve for high-speed compressible two-phase flows involving phase changing. Numerical examples include the cavitating flows induced by an ultrasonic oscillating horn with and without a counter sample. The numerical results by the proposed method are validated against the published experimental data as well as numerical results and good agreements have been obtained. Our calculation demonstrates that the proposed numerical method is applicable to the study of high-speed two phase flows with phase transition and wave propagation, such as shock waves induced by the collapse of the cavitation bubbles.

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