Investigating the Influence of Impeller Axial Thrust Balance Holes On the Flow and Overall Performance of a Cryogenic Liquid Turbine Expander

2021 ◽  
Author(s):  
Changjiang Huo ◽  
Jinju Sun ◽  
Peng Song ◽  
Shan Sun
Keyword(s):  
Cryogenic Liquid ◽  
Hole Diameter ◽  
Design Flow ◽  
Radial Position ◽  
Axial Component ◽  
Back Side ◽  
Axial Thrust ◽  
Gap Flow ◽  
Overall Performance ◽  
Overall Efficiency

Abstract An excessive rotor axial thrust in any turbomachine can cause critical operational problems, and rotor axial thrust balancing has always attracted much attention. The present numerical study is focused on axial thrust balancing for a cryogenic liquid turbine expander, whose axial thrust balancing is typically challenging because of its small impeller size and large axial thrust. A computational fluid dynamics (CFD) simulation is conducted in a real turbine expander environment constituted by main and gap flow domains with allowing for the thermodynamic effect of liquefied air. The balance hole influential mechanism on the main and gap flows is explored, and its influence on the expander axial thrust and overall performance is quantified. The results show that the use of balance holes creates a highly swirling gap flow, and the static pressure over the impeller disk back-side surface decreases to produce a small axial component force and axial thrust, but the turbine expander overall efficiency drops by 1.1 and 2.8 points at 100% and 50% design flow, respectively, due to an increased internal leakage loss and distorted impeller flow. In addition, a parametric study is conducted to analyze the effect of balance hole diameter, circumferential position and radial position on expander axial thrust and overall performance. The results indicate that the axial thrust is sensitive to both the balance hole diameter and circumferential position but less sensitive to its radial position, while the overall efficiency is influenced by all three parameters.

Prediction of Axial Thrust Load Acting on a Cryogenic Liquid Turbine Impeller

2011 ◽  
Author(s):  
Ke Wang ◽  
Jinju Sun ◽  
Zhilong He ◽  
Peng Song
Keyword(s):  
Cryogenic Liquid ◽  
Empirical Method ◽  
Main Flow ◽  
Back Side ◽  
Turbine Stage ◽  
Axial Thrust ◽  
Gap Flow ◽  
Flow Domain ◽  
Side Gap ◽  
Thrust Load

A single stage cryogenic liquid turbine is developed for replacing the Joule-Thompson valve and recovering energy from the liquefied air during throttling process in the large-scale internal compression air-separation unit, and evaluation of the impeller axial thrust at different conditions is essential for a reliable bearing design and stable operation. To predict the axial thrust load, a numerical model is established to simulate the turbine flow in a turbine stage environment, which includes the main flow domain (an asymmetrical volute, variable geometry nozzle, impeller, and diffuser), impeller front and back side gaps, and shaft seal leakage. Numerical simulation of flow is conducted by using the ANSYS-CFX. Flow characteristics in both main flow domain and impeller side gaps of the turbine stage are captured and analyzed. The axial thrust is then calculated based on the obtained pressure data in the impeller and its front and side gaps by using a direct integration approach. Flow behaviour in both main flow domain and impeller side gaps has been well exhibited by the numerical results. At the impeller back side gap inlet, the back flow is encountered even for design condition and it returns the impeller main flow stream; the impeller side gap flow has much influence on the axial thrust. To investigate influence of turbine operation condition on axial thrust, flow simulation is conducted at different mass flow rates and inlet pressure for the turbine stage, based on which the axial thrust is calculated. It is demonstrated from the obtained numerical results that the axial thrust increases as the inlet pressure increases and decreases as turbine flow rate increases. Geometry parametric study is conducted for the shaft seal clearances, which has demonstrated that the axial thrust is influenced largely by the clearance size and it decreases as the clearance grows. For the purpose of comparison, the empirical method is also used to predict the axial thrust load. The obtained results are compared to the numerical ones and evident deviation of the empirical from the numerical exists and the reason is that axial force components caused by the impeller main flow stream and its side gap flow are approximated very roughly in the empirical method.

ELECTRICAL BEHAVIOR OF A DOUBLE SIDED PV SOLAR PANEL

2011 ◽  
Vol 2011 (1) ◽  
pp. 000800-000804
Author(s):  
V. Ganescu ◽  
R. Shoaff ◽  
A. Pascu
Keyword(s):  
Thin Film ◽  
Power Output ◽  
Environmental Variables ◽  
Operating Conditions ◽  
Solar Panel ◽  
Back Side ◽  
Solar Pv ◽  
Electrical Behavior ◽  
Pv Module ◽  
Overall Efficiency

An innovative low power (5W) consumer grade dual face PV solar panel assembly is presented in this research. The authors propose capitalizing indirectly on the shadowed face of a typical solar panel by augmenting the panel’s total active area of exposure (via the panel’s “back side” and respective “deflectors”) and aiming at an increase in the overall efficiency of the assembly. Standard environmental operating conditions were taken into account. No CPV were used. The resulting power output profile of this unit is presented in detail and compared with the output of a single sided “standard” solar PV module configuration. In addition, under similar design and operating environmental variables, the behavior of crystalline cells panels is intended to be contrasted with thin film panels’ as variants of this proposed solution.

The Effects of Multiphase, Multi-Viscosity Fluids on Axial Thrust and Cooling Flow Performance of a Canned Motor Pump

2019 ◽  
Author(s):  
Eric Conaway ◽  
Jose Matos ◽  
Ryan Mesiano
Keyword(s):  
Multiphase Flow ◽  
Temperature Rise ◽  
Design Flow ◽  
Fluid Viscosity ◽  
Axial Thrust ◽  
Cooling Flow ◽  
Second Stage ◽  
Light Oil ◽  
Motor Cooling ◽  
Canned Motor

Abstract A canned motor pump for technology demonstration in subsea oil and gas systems was tested to provide data to understand the design, modeling and performance characteristics of a canned motor pump operating in multiphase flow. This paper discusses the impact of multiphase flow and fluid viscosity on axial thrust and motor cooling flow characteristics. The technology demonstrator is a two-stage, low specific speed (Ns∼550) centrifugal pump designed to deliver 140 gpm at 600 feet of head at 3930 rpm. The 61 hp canned motor is cooled by a small portion of the pump discharge fluid, which is drawn downward through the motor by pump out vanes on the hub of the second stage impeller. The multiphase test loop is equipped for both water and light oil operation in low pressure and ambient temperature conditions. Testing occurred over a range of conditions to simulate varying fluid properties and operating scenarios. Shaft rotational speed varied between 2000 and 4250 rpm with pump liquid flow rates from 25 to 250 gpm. These operating scenarios were repeated for both water and light oil (∼2 cP) with multiphase flow ranging from 0–20% gas volume fraction (GVF) using injected air. Testing results indicate a detectable impact from the different fluids and GVF’s tested, which can be related to features such as the second stage impeller pump-out vane and regions within the motor cavities. In water-air tests, increasing GVF led to the following: motor input power reduced by 5%; axial thrust increased by 100%; motor cooling fluid temperature rise increased by 100%; and pressure rise in the second stage pump out vanes reduced by 30% - directly impacting motor cooling flow rate, temperature rise, and axial thrust. In the oil-air tests, multiphase flow showed similar tendencies with reduced magnitude. Notably, the effects due to air injection do not appear at GVF below 15% with oil-air mixtures, unlike water-air tests which demonstrated effects across all GVFs. The test results provide insight into the behavior of variable viscosity, multiphase flow in the canned motor pump cooling passages, as driven by the second stage impeller pump out vanes. These observed characteristics can be used to design flow control features and evaluate operational impacts, while the performance data obtained can be used to assess the behavior of flow models for this application.

scholarly journals Study on effective parameter of the triple-pressure reheat combined cycle performance

2013 ◽  
Vol 17 (2) ◽  
pp. 497-508 ◽  
Author(s):  
Thamir Ibrahim ◽  
M.M. Rahman
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Compression Ratio ◽  
Combined Cycle ◽  
Total Power ◽  
Inlet Temperature ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet ◽  
Overall Performance ◽  
Overall Efficiency

The thermodynamic analyses of the triple-pressure reheat combined cycle gas turbines with duct burner are presented and discussed in this paper. The overall performance of a combined cycle gas turbine power plant is influenced by the ambient temperature, compression ratio and turbine inlet temperature. These parameters affect the overall thermal efficiency, power output and the heat-rate. In this study a thermodynamic model was development on an existing actual combined cycle gas turbine (CCGT) (In this case study, an effort has been made to enhance the performance of the CCGT through a parametric study using a thermodynamic analysis. The effect of ambient temperature and operation parameter, including compression ratio and turbine inlet temperature, on the overall performance of CCGT are investigated. The code of the performance model for CCGT power plant was developed utilizing the THERMOFLEX software. The simulating results show that the total power output and overall efficiency of a CCGT decrease with increase the ambient temperature because increase the consumption power in the air compressor of a GT. The totals power of a CCGT decreases with increase the compression rate, while the overall efficiency of a CCGT increases with increase the compression ratio to 21, after that the overall efficiency will go down. Far there more the turbine inlet temperature increases the both total power and overall efficiency increase, so the turbine inlet temperature has a strong effect on the overall performance of CCGT power plant. Also the simulation model give a good result compared with MARAFIQ CCGT power plant. With these variables, the turbine inlet temperature causes the greatest overall performance variation.

Numerical Investigation of a Cryogenic Liquid Turbine Performance and Flow Behavior

2008 ◽  
Author(s):  
Wei Zhao ◽  
Jinju Sun ◽  
Hezhao Zhu ◽  
Cheng Li ◽  
Guocheng Cai ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Large Scale ◽  
Flow Behavior ◽  
Cryogenic Liquid ◽  
Air Separation ◽  
Design Flow ◽  
Suction Surface ◽  
Navier Stokes Equation ◽  
Separation Unit ◽  
Turbine Performance

A single stage cryogenic liquid turbine is designed for a large-scale internal compression air-separation unit to replace the Joule-Thompson valve and recover energy from the liquefied air during throttling process. It includes a radial vaned nozzle, and 3-dimensional impeller. Numerical investigation using 3-D incompressible Navier-Stokes Equation together with Spalart-Allmaras turbulence model and mixing plane approach at the impeller and stator interface are carried out at design and off-design flow. At design condition, recovered shaft power has amounted to 185.87 kW, and pressure in each component decreases smoothly and reaches to the expected scale at outlet. At small flow rates, flow separation is observed near the middle section of blade suction surface, which may cause local vaporization and even cavitation. To further improve the turbine flow behavior and performance, geometry parametric study is carried out. Influence of radial gap between impeller and nozzle blade rows, and nozzle stagger angle on turbine performance are investigated and clarified. Results arising from the present study provide some guidance for cryogenic liquid turbine optimal design.

scholarly journals Flow Inside the Sidewall Gaps of Hydraulic Machines: A Review

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6617
Author(s):  
Lucie Zemanová ◽  
Pavel Rudolf
Keyword(s):  
Secondary Flow ◽  
Operating Characteristics ◽  
Axial Thrust ◽  
Numerical Studies ◽  
Current State ◽  
Hydraulic Machines ◽  
Disk Friction ◽  
Low Specific Speed ◽  
Overall Performance ◽  
Physical Phenomena

The paper critically reviews the current state of the art in flow inside sidewall gaps of hydraulic pumps and turbines. It describes the consequences of the presence of this type of flow in turbomachinery and then relates it to other physical phenomena that determine the behavior, operating characteristics, and overall performance of the machine. Despite the small dimensions of the rotor-stator spaces, the flow in these regions can significantly affect the overall flow field and, consequently, efficiency. The circulation of the fluid inside the gaps and secondary flow that is caused by rotating elements influences the disk friction losses, which is of great importance, especially in the case of low specific speed pumps and turbines. The flow pattern affects the pressure distribution inside a machine and, thus, generates axial thrust. The presence of secondary flow also significantly changes the rotordynamics and can bring about undesirable vibrations and acoustics issues. This article aims to review and summarize the studies that were conducted on the mentioned phenomena. Experimental and numerical studies are both taken into consideration. It proposes some requirements for prospective research in order to fill current gaps in the literature and reveals the upcoming challenges in the design of hydraulic machines.

An Experimental Verification of a New Design for Cantilevered Stators With Large Hub Clearances

2012 ◽  
Author(s):  
Martin Lange ◽  
Konrad Vogeler ◽  
Ronald Mailach ◽  
Sergio Elorza-Gomez
Keyword(s):  
Flow Field ◽  
Experimental Verification ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Performance Data ◽  
Axial Compressors ◽  
The Third ◽  
Overall Performance ◽  
Overall Efficiency ◽  
Aero Engines

Proportionally large relative radial clearances can be found within the rear stages of multistage axial compressors of gas turbines and aero engines, with significant impact on their efficiency. A new three-dimensional design for cantilevered stators in axial compressors is presented, with the aim of improving the overall efficiency and losses of rear stage vanes with large relative hub clearances. The new vane design comprises an unconventional dihedral, with special consideration to reduce the losses caused by the hub clearance vortex. The design was tested in a 4-stage low speed axial research compressor under rear stage conditions. The results are compared to the nominal design to validate the reduction of hub clearance losses and blockage. For both designs, the hub clearances over the third and fourth stator were varied from 1.5% up to 6.0% of span. Overall performance data and flow field traverses upstream and downstream of stator 3 and rotor 4 will be presented in this article in comparison with 3D CFD results.

Performance Estimation of Firms by G-L-A Supply Chain under Imperfect Data

2017 ◽  
pp. 245-277 ◽  
Author(s):  
Anoop Kumar Sahu ◽  
Nitin Kumar Sahu ◽  
Atul Kumar Sahu
Keyword(s):  
Supply Chain ◽  
Manufacturing Firms ◽  
Performance Estimation ◽  
Hypothetical Case ◽  
Centroid Method ◽  
Index Model ◽  
Imperfect Data ◽  
Case Research ◽  
Overall Performance ◽  
Overall Efficiency

Amongst various proposed SC philosophies, Lean, Green and Agile strategies of SC worked seminal to solve many problems of firms. Performance measurement acts as a tool to quantify overall efficiency via G-L-A SC activities of firm, where Green SC agenda is to control and diminish pollution and Lean SC helps to reduce waste of firm, while Agile SC target to manage SC more cum quick responding to clients. This chapter proposed a MCDM performance appraisement module (module constituted by mixing the segregated chain of green-lean-agile logistic activities and corresponding their interrelated metrics) conjunctive with Fuzzy Performance Index model in purpose to estimation the overall performance of individual firm. Furthermore, a centroid method coupled with fuzzy number set is proposed for classifying ill and strong G-L-A metrics of firm, so that managers could escalate their firms performance in case of non desirable performance. A hypothetical case research of two firms i.e. gear and shaft manufacturing firms are shown to measure their performance under G-LA supply chain.

Performance Estimation of Firms by G-L-A Supply Chain under Imperfect Data

2020 ◽  
pp. 999-1031
Author(s):  
Anoop Kumar Sahu ◽  
Nitin Kumar Sahu ◽  
Atul Kumar Sahu
Keyword(s):  
Supply Chain ◽  
Manufacturing Firms ◽  
Performance Estimation ◽  
Hypothetical Case ◽  
Centroid Method ◽  
Index Model ◽  
Imperfect Data ◽  
Case Research ◽  
Overall Performance ◽  
Overall Efficiency

Amongst various proposed SC philosophies, Lean, Green and Agile strategies of SC worked seminal to solve many problems of firms. Performance measurement acts as a tool to quantify overall efficiency via G-L-A SC activities of firm, where Green SC agenda is to control and diminish pollution and Lean SC helps to reduce waste of firm, while Agile SC target to manage SC more cum quick responding to clients. This chapter proposed a MCDM performance appraisement module (module constituted by mixing the segregated chain of green-lean-agile logistic activities and corresponding their interrelated metrics) conjunctive with Fuzzy Performance Index model in purpose to estimation the overall performance of individual firm. Furthermore, a centroid method coupled with fuzzy number set is proposed for classifying ill and strong G-L-A metrics of firm, so that managers could escalate their firms performance in case of non desirable performance. A hypothetical case research of two firms i.e. gear and shaft manufacturing firms are shown to measure their performance under G-LA supply chain.

A CFD Method for Axial Thrust Load Prediction of Centrifugal Compressors

2001 ◽  
Author(s):  
Zhen-Xue Han ◽  
Paul G. A. Cizmas
Keyword(s):  
Centrifugal Compressor ◽  
Stokes Equations ◽  
Least Squares Method ◽  
Directional Derivatives ◽  
Computational Domain ◽  
Back Side ◽  
Load Prediction ◽  
Time Step ◽  
Axial Thrust ◽  
Thrust Load

This paper presents the development of a numerical algorithm for the computation of axial thrust load on a centrifugal compressor. An unstructured flow solver has been developed for the computation of a hybrid, structured and unstructured grid. The computational domain of the impeller has been discretized using a structured mesh, while the computational domain on the back side of the wheel has been discretized using an unstructured mesh. The two grids are merged and a median dual-mesh is generated. The Navier-Stokes equations are discretized using a finite volume method. Roe’s flux-difference scheme is used for inviscid fluxes and directional derivatives along edges are used for viscous fluxes. The gradients at the mesh vertices are calculated using the Least-squares method. An explicit scheme is used for time integration. Convergence is accelerated using a local time-step and implicit residual smoothing. The results of the numerical simulation include the axial thrust load of the centrifugal compressor. In addition, details of the leakage flow are presented.

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