scholarly journals Experimental Monitoring of Vibration on Centrifugal Pump

2019 ◽  
pp. 283-286
Author(s):  
M. P. Kadam ◽  
R. S Shelke
Keyword(s):  
Significant Variation ◽  
Base Plate ◽  
Operating Conditions ◽  
Vibration Monitoring ◽  
Main Task ◽  
Flow Rates ◽  
Machine Failure ◽  
Plate Design ◽  
Parallel Misalignment ◽  
Fea Analysis

The main task of this Project was to summarize the reasons of turbo machine failure and a way of monitoring those causes during the operation of the turbo machine. Furthermore, the analysis of the results of Condition Monitoring (Vibration Monitoring) was explained with a practical experiment performed in the laboratory The results of our measurement indicate a significant variation in vibration trend as a function of operating conditions. The experimental results demonstrated that the vibration monitoring rig modeled various modes of machine failure. Failure can be caused either by single phenomenon or simultaneous phenomenon. Such phenomenon are as follows: Balancing Motor which can become unbalanced sometimes which will affect the measurement itself. Parallel Misalignment (misalignment of pump and motor) Blade pass and Vane pass Vortex shedding FEA Analysis for Modal, Random Vibrations Validation by FFT Base plate Design Furthermore, it can be emphasized that based on my observation during the measurement, when the revolution number was approaching 1500 [RPM], the noise of the turbo machine would dramatically increase when the flow rate was at its maximum. Thus, we can indicate that the noise was as result of high vibration. However, with the same revolution number (rotational speed) but lower flow rates the noise was not that much.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

Prediction of Hot Aisle Partition Airflow Boundary Conditions

2013 ◽  
Author(s):  
Zhihang Song ◽  
Bruce T. Murray ◽  
Bahgat Sammakia
Keyword(s):  
Boundary Conditions ◽  
Data Center ◽  
Computation Time ◽  
Design Tool ◽  
Operating Conditions ◽  
Ann Model ◽  
Flow Rates ◽  
Level Model ◽  
Optimization Methodology ◽  
Artificial Neural Network Ann

The integration of a simulation-based Artificial Neural Network (ANN) with a Genetic Algorithm (GA) has been explored as a real-time design tool for data center thermal management. The computation time for the ANN-GA approach is significantly smaller compared to a fully CFD-based optimization methodology for predicting data center operating conditions. However, difficulties remain when applying the ANN model for predicting operating conditions for configurations outside of the geometry used for the training set. One potential remedy is to partition the room layout into a finite number of characteristic zones, for which the ANN-GA model readily applies. Here, a multiple hot aisle/cold aisle data center configuration was analyzed using the commercial software FloTHERM. The CFD results are used to characterize the flow rates at the inter-zonal partitions. Based on specific reduced subsets of desired treatment quantities from the CFD results, such as CRAC and server rack air flow rates, the approach was applied for two different CRAC configurations and various levels of CRAC and server rack flow rates. Utilizing the compact inter-zonal boundary conditions, good agreement for the airflow and temperature distributions is achieved between predictions from the CFD computations for the entire room configuration and the reduced order zone-level model for different operating conditions and room layouts.

scholarly journals Metrological performance of single-jet water meters over time

2018 ◽  
Vol 13 (5) ◽  
pp. 1
Author(s):  
Carmen Virginia Palau ◽  
Juan Manzano ◽  
Iban Balbastre Peralta ◽  
Benito Moreira de Azevedo ◽  
Guilherme Vieira do Bomfim
Keyword(s):  
Measurement Error ◽  
Water Consumption ◽  
Operating Conditions ◽  
Economic Losses ◽  
Flow Rates ◽  
Metrological Operation ◽  
Operation Period ◽  
Single Jet ◽  
Water Meters ◽  
Over Time

To maintain quality measurement of water consumption, it is necessary to know the metrology of single-jet water meters over time. Knowing the accuracy of these instruments over time allows establishing a metrological operation period for different flow rates. This will aid water companies to optimize management and reduce economic losses due to unaccounted water consumption. This study analyzed the influence of time on the measurement error of single-jet water meters to evaluate the deterioration of the equipment and, with that, launch the metrological operation period. According to standards 8316 and 4064 of the International Organization for Standardization (ISO), 808 meters of metrological Class B were evaluated in six water supplies, with age ranges of 3.7 to 16.4 years of use. The measurement error was estimated by comparing the volume measured in a calibrated tank with the volume registered by the meters at flow rates of 30, 120, 750 and 1,500 L h-1. The metrological operation period of the meters was obtained for each flow rate by the relation between error of measurement and time of use (simple linear regression). According to the results, the majority of the equipment presents increasing under-registration errors over time, more pronounced at low flow rates and with less favorable operating conditions. The metrological operation period for flow rates of 30, 120, 750 and 1,500 L h-1 is estimated at approximately 3, 8, 14 and 13 years. This operation period combined with consumption patterns of users will establish the best time to replace the meters.

Subsynchronous Vibration Patterns Under Reduced Oil Supply Flow Rates

2017 ◽  
Author(s):  
B. R. Nichols ◽  
R. L. Fittro ◽  
C. P. Goyne
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Operating Conditions ◽  
System Stability ◽  
Supporting Evidence ◽  
Test Rig ◽  
Flow Rates ◽  
Oil Supply ◽  
Bending Mode ◽  
Wide Range

Many high-speed, rotating machines across a wide range of industrial applications depend on fluid film bearings to provide both static support of the rotor and to introduce stabilizing damping forces into the system through a developed hydrodynamic film wedge. Reduced oil supply flow rate to the bearings can cause cavitation, or a lack of a fully developed film layer, at the leading edge of the bearing pads. Reducing oil flow has the well-documented effects of higher bearing operating temperatures and decreased power losses due to shear forces. While machine efficiency may be improved with reduced lubricant flow, little experimental data on its effects on system stability and performance can be found in the literature. This study looks at overall system performance of a test rig operating under reduced oil supply flow rates by observing steady-state bearing performance indicators and baseline vibrational response of the shaft. The test rig used in this study was designed to be dynamically similar to a high-speed industrial compressor. It consists of a 1.55 m long, flexible rotor supported by two tilting pad bearings with a nominal diameter of 70 mm and a span of 1.2 m. The first bending mode is located at approximately 5,000 rpm. The tiling-pad bearings consist of five pads in a vintage, flooded bearing housing with a length to diameter ratio of 0.75, preload of 0.3, and a load-between-pad configuration. Tests were conducted over a number of operating speeds, ranging from 8,000 to 12,000 rpm, and bearing loads, while systematically reducing the oil supply flow rates provided to the bearings under each condition. For nearly all operating conditions, a low amplitude, broadband subsynchronous vibration pattern was observed in the frequency domain from approximately 0–75 Hz. When the test rig was operated at running speeds above its first bending mode, a distinctive subsynchronous peak emerged from the broadband pattern at approximately half of the running speed and at the first bending mode of the shaft. This vibration signature is often considered a classic sign of rotordynamic instability attributed to oil whip and shaft whirl phenomena. For low and moderate load conditions, the amplitude of this 0.5x subsynchronous peak increased with decreasing oil supply flow rate at all operating speeds. Under the high load condition, the subsynchronous peak was largely attenuated. A discussion on the possible sources of this subsynchronous vibration including self-excited instability and pad flutter forced vibration is provided with supporting evidence from thermoelastohydrodynamic (TEHD) bearing modeling results. Implications of reduced oil supply flow rate on system stability and operational limits are also discussed.

Numerical Analysis of the Flow Inside a Centrifugal Compressor’s Vaneless Diffuser and Volute

2001 ◽  
Author(s):  
Hooman Rezaei ◽  
Abraham Engeda ◽  
Paul Haley
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Mass Flow ◽  
Operating Conditions ◽  
Vaneless Diffuser ◽  
Flow Angle ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Minimum Medium ◽  
Good Agreement

Abstract The objective of this work was to perform numerical analysis of the flow inside a modified single stage CVHF 1280 Trane centrifugal compressor’s vaneless diffuser and volute. Gambit was utilized to read the casing geometry and generating the vaneless diffuser. An unstructured mesh was generated for the path from vaneless diffuser inlet to conic diffuser outlet. At the same time a meanline analysis was performed corresponding to speeds and mass flow rates of the experimental data in order to obtain the absolute velocity and flow angle leaving the impeller for those operating conditions. These values and experimental data were used as inlet and outlet boundary conditions for the simulations. Simulations were performed in Fluent 5.0 for three speeds of 2000, 3000 and 3497 RPM and mass flow rates of minimum, medium and maximum. Results are in good agreement with the experimental ones and present the flow structures inside the vaneless diffuser and volute.

An Artificial Intelligence Based Method for Performance Prediction and Inverse Design of Hydraulic Turbochargers

2020 ◽  
Author(s):  
Azam Thatte ◽  
Ganesh Vurimi ◽  
Prabhav Borate ◽  
Teymour Javaherchi
Keyword(s):  
Neural Network ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Inverse Design ◽  
Geometrical Parameters ◽  
Total Efficiency ◽  
Design Algorithm ◽  
Flow Rates ◽  
Radial Turbine ◽  
Radial Pump

Abstract A neural network based method is developed that can learn the underlying physics of hydraulic turbocharger (a radial pump coupled with a radial turbine) from a set of sparse experimental data and can predict the performance of a new turbocharger design for any given set of previously unseen operating conditions and geometric parameters. The novelty of the algorithm is that it learns the underlying physical mechanisms from a very sparse data spanning a broad range of flow rates and geometrical size brackets and uses these deeper common features recognized through a “mass-learning process” to predict the full performance curves for any given single geometry. The deep learning algorithm is able to accurately predict the key performance parameters like total efficiency of the turbocharger, its operating speed, pressure rise provided by the radial pump of the turbocharger and the shaft power produced by the radial turbine of the turbocharger for any given input combination of pump and turbine flow rates, differential pressure across the turbine and a limited set of geometrical parameters of pump and turbine impellers and volutes. Lastly, a novel method for fast inverse design of turbomachinery using a physics trained neural network and a constrained optimization algorithms is developed. The algorithm uses Nelder-Mead and Interior Point methods to find the global minimum of turbocharger design objective function in multi-dimensional space. The newly developed method is found to be very efficient in optimizing turbomachinery design problems with both equality and inequality constraints. The inverse design algorithm is able to successfully recommend an optimal combination of geometrical parameters like pump blade exit angle, pump impeller diameter, blade width, eye diameter, turbine nozzle diameter and rotational speed for a given target efficiency and head rise requirements. The preliminary results from this study indicate that it has a great potential to minimize the need for expensive 3D CFD based methods for the design of turbomachinery.

On Possibilities of Using Relative Shaft Vibration Signals for Rotating Blades Monitoring

2018 ◽  
Author(s):  
Jindrich Liska ◽  
Vojtech Vasicek ◽  
Jan Jakl
Keyword(s):  
Steam Turbine ◽  
Operating Conditions ◽  
Vibration Monitoring ◽  
Monitoring Systems ◽  
Blade Vibration ◽  
Vibration Signals ◽  
Rotating Blades ◽  
Timing Measurement ◽  
Blade Tip ◽  
Shaft Vibration

Ensuring the reliability of the steam turbine is the key for its long life. For this purpose monitoring systems are standardly used. Early detection of any failure can avoid possible economical and material losses. A monitoring of rotating blades vibration belongs to the very important tasks of the turbomachinery state assessment. Especially in terms of the last stages of low-pressure part, where the longest blades are vibrating at most. Commonly used methods for blade vibration monitoring are based on contact measurement using strain gauges or non-contact approach based on blade tip timing measurement. Rising demand for low-cost monitoring systems has initiated development of a new approach in blade vibration monitoring task. The presented approach is based on usage of relative rotor vibration signals. Its advantage is in using of standardly installed sensors making this approach economically interesting for the turbine operators compared to the traditionally used methods, mentioned above. This paper summarizes the symptoms of blade vibration phenomenon in relative shaft vibration signals, the impact of operating conditions on the blade vibration amplitude and its comparison to blade tip-timing measurement results. In addition of several examples, the article also describes an evaluation of proposed method in operation of steam turbine with power of 170MW.

Rotor Damped Natural Frequencies and Stability Under Reduced Oil Supply Flow Rates to Tilting-Pad Journal Bearings

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Bradley R. Nichols ◽  
Roger L. Fittro ◽  
Christopher P. Goyne
Keyword(s):  
Experimental Data ◽  
Natural Frequencies ◽  
Dynamic Performance ◽  
Operating Conditions ◽  
System Stability ◽  
Flow Rates ◽  
Oil Supply ◽  
Pressure Profiles ◽  
Tilting Pad ◽  
Identification Technique

Reduced oil supply flow rates in fluid film bearings can cause cavitation, or lack of a fully developed film layer, over one or more of the pads due to starvation. Reduced oil flow has the well-documented effects of higher bearing operating temperatures and decreased power losses; however, little experimental data are available on its effects on system stability and dynamic performance. The study looks at the effects of oil supply flow rate on dynamic bearing performance by comparing experimentally identified damped natural frequencies and damping ratios to predictive models. A test rig consisting of a flexible rotor and supported by two tilting pad bearings in flooded housings is utilized in this study. Tests are conducted over a range of supercritical operating speeds and bearing loads while systematically reducing the oil supply flow rates provided to the bearings. Shaft response measured as a magnetic actuator is used to perform sine sweep excitations of the rotor. A single-input, multiple-output system identification technique is then used to obtain frequency response functions (FRFs) and modal parameters. All experimental results are compared to predicted results obtained from bearing models based on thermoelastohydrodynamic (TEHD) lubrication theory. Both flooded and starved model flow assumptions are considered and compared to the data. Differences in the predicted trends of the models and the experimental data across varying operating conditions are examined. Predicted pressure profiles and dynamic coefficients from the models are presented to help explain any differences in trends.

Parametric Analysis of Single-Phase and Two-Phase Models of a Microfluidic Direct Methanol Fuel Cell

2013 ◽  
Author(s):  
Usama Tohid ◽  
Arturo Pacheco-Vega
Keyword(s):  
Fuel Cell ◽  
Parametric Analysis ◽  
Single Phase ◽  
Operating Conditions ◽  
Cell Performance ◽  
Geometrical Parameters ◽  
Two Phase ◽  
Flow Rates ◽  
Direct Methanol ◽  
Phase Models

We perform numerical simulations of single-phase and two-phase models of a direct methanol microfluidic fuel cell (μ-DMFC). The focus of this study is on the parametric analysis of a single channel of the system, for specific sets of operating conditions, in order to map the dependence of the cell performance with respect to the geometrical parameters. Different geometries, ranging from 500 μm to 4 mm in width, and 500 μm to 4 cm in length, along with membrane thicknesses from 50 μm to 500 μm, were considered. The mathematical models are given in terms of the Navier-Stokes, the Butler-Volmer and the Maxwell-Stefan equations, along with Darcy’s equation for the flow across the membrane. The difference between the single- and two-phase flow models lies upon the specific constitutive equations used. For each geometry and operating condition, the two-dimensional equations were solved by a finite element method. The conditions of operation include: flow rates and inlet weight fractions of methanol at the anode and oxygen the cathode. The results from this analysis, presented as polarization curves and power densities, indicate that fuel-cell systems with higher flow rates and inlet weight fraction of methanol achieve the best performance. However, when the concentration of methanol exceeds 2M the cell performance is negatively impacted due to crossover. Comparison of the results indicates that the two-phase model has a more restrictive domain for both the geometrical parameters and operating conditions.

scholarly journals Dynamic analysis of liquid annular seals with herringbone grooves on the rotor based on the perturbation method

2018 ◽  
Vol 5 (6) ◽  
pp. 180101 ◽  
Author(s):  
Lulu Zhai ◽  
Zhang Zhenjie ◽  
Chi Zhonghuang ◽  
Guo Jia
Keyword(s):  
Dynamic Characteristics ◽  
Operating Conditions ◽  
Geometric Parameters ◽  
Leakage Flow ◽  
Flow Rates ◽  
Rotordynamic Coefficients ◽  
Sealing Performance ◽  
Spiral Angle ◽  
Herringbone Grooves ◽  
Annular Seals

Annular seals have significant effects on the hydraulic and rotordynamic performances of turbomachinery. In this paper, an analysis method for calculating the leakage flow rates and dynamic characteristics of liquid annular seals with herringbone grooves on the rotor is proposed and verified. Leakage flow rates and dynamic characteristics of the model seals under different operating conditions are theoretically analysed and compared with those of plain and spiral-grooved seals of the same size. In addition, the influence of geometric parameters such as spiral angle and the lengths of the constituent parts on the sealing and rotordynamic coefficients of seals with herringbone grooves are also discussed. The results show that seals with herringbone grooves have better sealing performance, while providing better support actions and damping characteristics than the other two seal types under the same operating conditions. The seal geometric parameters including spiral angle, the lengths of the constituent parts and the clearance value have a significant influence on the dynamic characteristics of seals with herringbone grooves.

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