Integral Pumping Devices for Dual Mechanical Seals: Hydraulic Performance Generalization Using Dimensional Analysis

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Hassan A. Warda ◽  
Ihab G. Adam ◽  
Ahmed B. Rashad ◽  
Muhannad W. Gamal-Aldin
Keyword(s):  
Rotational Speed ◽  
Radial Flow ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
American Petroleum Institute ◽  
Mechanical Seals ◽  
Characteristic Curves ◽  
Outlet Port ◽  
Operation Conditions ◽  
Generalized Curves

An experimental study is carried out investigating hydraulic performance for various designs of dual-mechanical-seal cartridges with integral pumping-rings. The tested devices are classified into two main families: radial-flow and axial-flow. The radial-flow family utilizes the modified-paddle-wheel (MPW) pumping ring with either a radial or a tangential oriented cartridge outlet port, while the axial-flow family utilizes the pumping scroll (PS) pumping ring in the following cartridge-geometries: single-pumping-scroll (SS) and double-pumping-scroll (DS); as both types can be of either a radial or a tangential outlet port; and of an internal clearance value complying with American Petroleum Institute (API) 682 standard or smaller clearance. An experimental setup is constructed, and appropriate instrumentation is employed to measure inlet pressure, outlet pressure, rotational speed, and barrier fluid flow rate acquiring flow-head characteristic curves. Moreover, empirical generalized characteristic curves are deduced from experimental observations obtained from the present study and previous companion work. The generalized curves can be employed in estimating pumping ring performance for a different size or other operation conditions such as varying rotational speed or fluid type. They can be also utilized to validate numerical simulations for geometrically similar designs.

Integral Pumping Devices for Dual Mechanical Seals: Experiments and Numerical Simulations

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
H. A. Warda ◽  
E. M. Wahba ◽  
E. A. Selim
Keyword(s):  
Numerical Simulations ◽  
Rotational Speed ◽  
Numerical Study ◽  
Axial Flow ◽  
Radial Clearance ◽  
Inlet Temperature ◽  
Mechanical Seals ◽  
Outlet Port ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Reference

An experimental and numerical investigation is carried out to evaluate the performance of alternative pumping ring designs for dual mechanical seals. Both radial-flow and axial-flow pumping rings are considered in the present study. An experimental setup is constructed, and appropriate instrumentation are employed to measure the pressure, temperature, and flow rate of the barrier fluid. A parametric study is carried out to investigate the effect of pump rotational speed, barrier fluid accumulator pressure, and barrier fluid inlet temperature on the performance of the pumping rings. Experiments are also used to evaluate the effect of different geometric parameters such as the radial clearance between the pumping ring and the surrounding gland, and the outlet port orientation. Moreover, a numerical study is conducted to simulate the flow field for the radial pumping ring designs under different operating parameters. The computational fluid dynamics (CFD) model implements a multiple reference frame (MRF) technique, while turbulence is modeled using the standard k-epsilon model. Numerical simulations are also used to visualize the flow of the barrier fluid within the dual seal cavity. Present results indicate that the pump rotational speed and the orientation of the outlet port have a significant effect on the performance of the pumping ring. On the other hand, the effects of barrier fluid accumulator pressure and inlet temperature are minimal on the performance. The study also shows that reducing the radial clearance between the rotating ring and the stationary outer gland would significantly improve the performance of axial pumping rings. Moreover, comparisons between the computational and experimental results show good agreement for pumping ring configurations with tangential outlet (TO) ports and at moderate rotational speeds.

Aerodynamics of Contra-Rotating Fans With Swept Blades

2015 ◽  
Author(s):  
K. Vijayraj ◽  
M. Govardhan
Keyword(s):  
Rotational Speed ◽  
Axial Flow ◽  
Pressure Rise ◽  
Aerodynamic Performance ◽  
The Other ◽  
Flow Structures ◽  
Current Investigation ◽  
Rotating System ◽  
Stall Margin ◽  
Static Head

A Counter-Rotating System (CRS) is composed of a front rotor and a rear rotor which rotates in the opposite direction. Compared with traditional rotor-stator system, the rear rotor is used not only to recover the static head but also to supply energy to the fluid. Therefore, to achieve the same performance, the use of a CRS may lead to a reduction of the rotational speed and may generate better homogeneous flow downstream of the stage. On the other hand, the mixing area in between the two rotors induces complicated interacting flow structures. Blade sweep has attracted the turbomachinery blade designers owing to a variety of performance benefits it offers. However, the effect of blade sweep on the performance, stall margin improvements whether it is advantageous/disadvantageous to sweep one or both rotors has not been studied till now. In the current investigation blade sweep on the performance characteristics of contra rotating axial flow fans are studied. Two sweep schemes (axial sweeping and tip chord line sweeping) are studied for two sweep angles (20° and 30°). Effect of blade sweep on front rotor and rear rotor are dealt separately by sweeping one at a time. Both rotors are swept together and effect of such sweep scheme on the aerodynamic performance of the stage is also reported here. The performance of contra rotating fan is significantly affected by all these parameters. Blade sweep improved the pressure rise and stall margin of front rotors. Axially swept rotors are found to have higher pressure rise with reduced incidence losses near the tip for front rotors. Sweeping the rear rotor is not effective since the pressure rise is less than that of unswept rotor and also has less stall margin.

Blade Loadings for Hovercraft and other Radial Flow Fans

1967 ◽  
Vol 9 (4) ◽  
pp. 265-277 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Radial Flow ◽  
Axial Flow ◽  
Maximum Temperature ◽  
Centrifugal Fan ◽  
Blade Loading ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Flow Compressor ◽  
High Work ◽  
Outside Diameter

The layout of a hovercraft leads naturally to the choice of a radial outward flow fan, but the aerodynamic requirements are more stringent than those normally associated with industrial fans. In this paper a blade loading criterion used extensively in axial flow compressor practice has been adapted to the more general case of radial flow fans. Using this criterion maximum fluid deflections and maximum temperature rise coefficients have been calculated. It is shown that fluid deflections in radial fans should be substantially lower than those in axial flow machines. For high work output the ratio of rotor outside diameter to rotor inside diameter should be as close to unity as is mechanically possible. Inlet guide vanes would be of no benefit to the conventional industrial type centrifugal fan, but for such applications as hovercraft inlet guide vanes could be most beneficial. The paper outlines those areas in which further research is necessary fully to confirm the approach, and hence the quantitative values, given in this paper.

Aerodynamic Performance Evaluation of Axial Flow Fan Using Numerical Techniques

2021 ◽  
Author(s):  
Raghuvaran D. ◽  
Satvik Shenoy ◽  
Srinivas G
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Total Pressure ◽  
Axial Flow ◽  
High Mass ◽  
Ansys Fluent ◽  
Industrial Sectors ◽  
Mass Flow Rates

Abstract Axial flow fans (AFF) are extensively used in various industrial sectors, usually with flows of low resistance and high mass flow rates. The blades, the hub and the shroud are the three major parts of an AFF. Various kinds of optimisation can be implemented to improve the performance of an AFF. The most common type is found to be geometric optimisation including variation in number of blades, modification in hub and shroud radius, change in angle of attack and blade twist, etc. After validation of simulation model and carrying out a grid independence test, parametric analysis was done on an 11-bladed AFF with a shroud of uniform radius using ANSYS Fluent. The rotational speed of the fan and the velocity at fan inlet were the primary variables of the study. The variation in outlet mass flow rate and total pressure was studied for both compressible and incompressible ambient flows. Relation of mass flow rate and total pressure with inlet velocity is observed to be linear and exponential respectively. On the other hand, mass flow rate and total pressure have nearly linear relationship with rotational speed. A comparison of several different axial flow tracks with the baseline case fills one of the research gaps.

Fish-friendly design of an axial flow pump impeller based on a blade strike model

2019 ◽  
Vol 234 (2) ◽  
pp. 173-186 ◽  
Author(s):  
Qiang Pan ◽  
Weidong Shi ◽  
Desheng Zhang ◽  
BPM van Esch ◽  
Ruijie Zhao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Behavior ◽  
Integrated Design ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Fish Mortality ◽  
Computational Fluid Dynamics Analysis ◽  
Axial Flow Pump ◽  
Flow Pump

With environmental awareness growing in many countries, governments are taking measures to reduce mortality of migrating fish in pumping stations. Manufacturers seek to develop pumps that are less damaging to fish and still provide good hydraulic performance, but little is known about the implications design modifications may have on internal flow characteristics and overall hydraulic performance. In this paper, an integrated design method is proposed that combines a validated blade strike model for fish damage and a computational fluid dynamics method to assess the pump performance. A redesign of an existing, conventional, axial flow pump is presented as an example in this paper. It shows how the design of the impeller blades was modified stepwise in order to reduce fish mortality while its hydraulic performance was monitored. Computational fluid dynamics analysis of the flow near the hub of the highly skewed blades indicated that unconventional design modifications were required to ensure optimum flow behavior. In the final fish-friendly design, the risk of fish mortality has reduced considerably while the hydraulic performance of the pump is still acceptable for practical application.

scholarly journals Effect of Suction and Discharge Conditions on the Unsteady Flow Phenomena of Axial-Flow Reactor Coolant Pump

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1592
Author(s):  
Xin Chen ◽  
Shiyang Li ◽  
Dazhuan Wu ◽  
Shuai Yang ◽  
Peng Wu
Keyword(s):  
Unsteady Flow ◽  
Pressure Pulsation ◽  
Flow Reactor ◽  
Axial Flow ◽  
Hydraulic Performance ◽  
Uniform Flow ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Flow Phenomena ◽  
Rotating Impeller

In order to study the effects of the suction and discharge conditions on the hydraulic performance and unsteady flow phenomena of an axial-flow reactor coolant pump (RCP), three RCP models with different suction and discharge configurations are analyzed by computational fluid dynamics (CFD) method. The CFD results are validated by experimental data. The hydraulic performance of the three RCP models shows little difference. However, the unsteady flow phenomena of RCP are significantly affected by the variation of suction and discharge conditions. Compared with that of Model E-S (baseline, elbow-single nozzle), the pressure pulsation in rotating frame of Model S-S (straight pipe-single nozzle) and Model E-D (elbow-double nozzles) is weakened in different degrees and forms, due to the more uniform flow fields upstream and downstream of the impeller, respectively. It indicates that the generalized rotor-stator interaction (RSI) actually exists between the rotating impeller and all stationary components causing the circumferentially non-uniform flow. Furthermore, improving the circumferential uniformity of the flow upstream and downstream of impeller (suction and discharge flow) also contributes to reducing the radial dynamic fluid force acting on the impeller. Compared with those of Model E-S, the dynamic FX and FY of Model S-S are severely weakened, and those of Model E-D also gain a minor amplitude decrease at fBPF. In contrast, the general pressure pulsation in fixed frame is mainly related to the rotating impeller and barely affected by the suction and discharge conditions.

scholarly journals Studies on S-shaped draft tube for low head axial flow turbine (Internal flow and hydraulic performance)

1986 ◽  
Vol 52 (474) ◽  
pp. 585-592 ◽  
Author(s):  
Yukimaru SHIMIZU ◽  
Takashi KUBOTA ◽  
Fusanobu NAKAMURA ◽  
Shogo NAKAMURA
Keyword(s):  
Draft Tube ◽  
Axial Flow ◽  
Internal Flow ◽  
Hydraulic Performance ◽  
Low Head

Analysis of Local Flow Structure and Global Compressor Performance During Rotating Stall

2004 ◽  
Author(s):  
Chiara Palomba
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Rotational Speed ◽  
Axial Flow ◽  
Rotating Stall ◽  
Performance Parameters ◽  
Flow Conditions ◽  
Local Flow ◽  
Flow Parameters ◽  
Compressor Performance

Rotating stall is an instability phenomenon that arises in axial flow compressors when the flow is reduced at constant rotational speed. It is characterised by the onset of rotating perturbations in the flow field accompanied by either an abrupt or gradual decrease of performances. Although the flow field is unsteady and non axisymmetric, the global operating point is stable and a stalled branch of performance curve may be experimentally determined. The number, rotational speed, circumferential extension of the rotating perturbed flow regions named rotating cells may vary from one compressor to another and may depend on the throttle position. The present work focuses on the interaction between local flow parameters and global compressor performance parameters with the aim of reaching a better understanding of the phenomenon. Starting from the Day, Greitzer and Cumpsty [1] model the detailed flow conditions during rotating stall are studied and related to the global performance parameters. This is done both to verify if the compressor under examination fits to the model and if the detailed flow structure may highlight the physics that in the simple model may hide behind the correlation’s used.

Numerical Investigations on the Power Generation of Turbo-Expander During the Propane De-Hydrogenation Process

2019 ◽  
Author(s):  
Hwabhin Kwon ◽  
Heesung Park
Keyword(s):  
Power Generation ◽  
Rotational Speed ◽  
Mechanical Energy ◽  
Pressure Ratio ◽  
Electrical Power ◽  
Operating Conditions ◽  
Hydrogenation Process ◽  
Operation Conditions ◽  
Turbo Expander ◽  
Discharge Pressure

Abstract A turboexpander for the propane de-hydrogenation process with blade and splitter has been numerically investigated. Since the turboexpander expands fluid from higher inlet pressure to lower discharge pressure, the kinetic energy of fluid is converted into useful mechanical energy. The efficiency and power generation with the designed turboexpander have been simulated with different operating conditions. The pressure ratio between inlet and outlet and rotational speed are varied to characterize the performance of the turboexpander as an electrical power generator. The numerical simulations have shown the vortex at the trailing edges of blade and splitter which decreases the efficiency. The rotational speed and the pressure ratio are parameterized to obtain operation conditions which achieve high power generation and efficiency. Consequently, the generated power from 614.12 kW to 693.45kW is obtained at the normal rotational speed and the pressure ratio between 1.75 to 2.22.

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