Cavitation Properties of Liquids

1964 ◽  
Vol 86 (2) ◽  
pp. 195-199 ◽  
Author(s):  
A. J. Stepanoff
Keyword(s):  
Thermal Properties ◽  
Molten Metal ◽  
Test Data ◽  
Centrifugal Pumps ◽  
Cavitation Behavior ◽  
Sufficient Test

A method of representing the thermal properties of liquids is offered such that cavitation behavior of centrifugal pumps handling any liquid—molten metal, hydrocarbons, cryogenics—can be accurately evaluated. Sufficient test data are available to illustrate the use of the method. The paper is a supplement to the article published earlier [1] by the author.

An Assessment of Branch Technical Position 5-3 to Determine Unirradiated RTNDT for SA-508 Cl. 2 Forgings

2014 ◽  
Author(s):  
Greg Troyer ◽  
Matthew DeVan
Keyword(s):  
Measurement Uncertainty ◽  
Test Data ◽  
Reactor Vessel ◽  
Reference Temperature ◽  
The Us ◽  
Extended Operation ◽  
Test Requirements ◽  
Sufficient Test

10 CFR 50.61 and 10 CFR 50, Appendix G require the evaluation of the unirradiated nil ductility transition reference temperature (RTNDT) determined in accordance with ASME Section III, paragraph NB-2331. For extended operation, components outside of the traditional beltline may require evaluation of RTNDT per NB-2331. Many of these components do not have sufficient test data to determine RTNDT in accordance with NB-2331 due to different test requirements during fabrication. The US NRC has provided methods in Branch Technical Position (BTP) 5-3 of NUREG 0800 to estimate a bounding RTNDT for these components using available test data. This paper compares Branch Technical Position 5-3, paragraph 1.1(4) estimates of RTNDT using 10°F Charpy V-notch data to the ASME B&PV Section III, Paragraph NB-2331 values of RTNDT, for a sample of 35 SA-508 Cl. 2 reactor vessel shell forgings. The BTP 5-3, Paragraph 1.1(4) estimates underestimate NB-2331 values by an average of 13.8°F and by as much as 40°F. This non-conservatism is attributed to the use of 10°F Charpy V-notch data for the BTP 5-3, paragraph 1.1(4) estimate and the difficulty of using only Charpy V-notch data to estimate a parameter based on Charpy V-notch and dropweight data. If BTP 5-3, paragraph 1.1(4) estimates for RTNDT are to be used in 10 CFR 50.61 and 10 CFR 50 Appendix G calculations, the bias and measurement uncertainty of BTP 5-3, paragraph 1.1(4) should be accounted for, such that the estimate of RTNDT bounds the NB-2331 RTNDT with 2σ confidence, as shown in Regulatory Guide 1.99, Revision 2.

The Rotating Cavitation Performance of a Centrifugal Pump with a Splitter-Bladed Inducer under Different Rotational Speed

2015 ◽  
Vol 32 (3) ◽  
Author(s):  
XiaoMei Guo ◽  
ZuChao Zhu ◽  
BaoLing Cui ◽  
Yi Li
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
High Speed ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Cavitation Flow ◽  
Operation Condition ◽  
Cavitation Performance ◽  
Cavitation Behavior ◽  
Suction Performance

AbstractDesigning inducer is one of the effective ways to improve the suction performance of high-speed centrifugal pumps. The operation condition including rotational speeds can affect the internal flow and external performance of high-speed centrifugal pumps with an inducer. In order to clarify the rotating cavitation performance of a centrifugal pump with a splitter-bladed inducer under different rotational speed, a centrifugal pump with a splitter-bladed inducer is investigated in the work. By using Rayleigh–Plesset equations and Mixture model, the cavitation flow of centrifugal pump is numerically simulated, as well as the external performance experimental test is carried out. It is found that the cavitation area increases with the rotational speeds. The location of the passage where cavitation is easy to appear is explored. Asymmetric cavitation behavior is observed. That, the trail of the inducer is easy to take cavitation when the rotational speed is increased to a degree, is also observed. The trend of

The Effect of Misalignment on the Fatigue Life of Tapered Roller Bearings

1972 ◽  
Vol 94 (2) ◽  
pp. 181-186 ◽  
Author(s):  
H. Zantopulos
Keyword(s):  
Experimental Study ◽  
Fatigue Life ◽  
Test Data ◽  
Load Distribution ◽  
Roller Bearings ◽  
Bearing Life ◽  
Life Tests ◽  
Tapered Roller ◽  
Tapered Roller Bearings ◽  
Sufficient Test

A comprehensive analytical and experimental study of the effect of misalignment on load distribution and fatigue life of tapered roller bearings is presented. Included are the effects of truncation of crowned rollers and edge of contact stresses. Bearing life tests, involving approximately 500 bearings, were run at various loads and misalignments to obtain sufficient test data to substantiate the analytical results.

Dynamic Performance Characteristics of Floating-Ring Bearings With Varied Oil-Injection Swirl-Control Angles

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Daniel Tamunodukobipi ◽  
Chang Ho Kim ◽  
Yong-Bok Lee
Keyword(s):  
Test Data ◽  
Hydrodynamic Instability ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Efficient Solutions ◽  
Test Results ◽  
Clearance Ratio ◽  
Thermal Growth ◽  
Oil Injection ◽  
Sufficient Test

Hydrodynamic instability is a prime causative of performance irregularities and violent vibrations in floating-ring bearing (FRB) supported turbosystems. The quest for energy-efficient solutions to this has stimulated the development of diverse FRB design-geometries, dimensional relationships, and surface-contours. Unfortunately, these modifications are characterized mainly by model-predictors, which results lack sufficient test-data to benchmark their authenticities. This work presents the concept and the test-data of flow redirection in FRBs by using an oil-injection swirl-control mechanism (OISCM) to attenuate rotordynamic instabilities. FRBs with radius ratio = 1.75 and clearance ratio = 1.5 are tested for various OISCM angles (0 deg, 30 deg, and 60 deg) and under a specific load = 50 kN/m2. The test results indicate that FRBs with OISCM demonstrate substantial improvements in damping and stability characteristics. Their whirl-frequency-ratio (WFR) and cross-coupled forces are lower because of improved symmetry of films' pressure-forces (Kxx ≈ Kyy). Although the magnitudes of direct damping are higher (|Cxx| = 16.92 kN s/m for 60 deg and 6.03 kN s/m for 0 deg), the load capacity (Kxx) is slightly lower than the normal (0 deg), injection. Nonetheless, this discrepancy in load capacities becomes insignificant for speeds above 22 krpm. The WFR and subsynchronous amplitudes, which are graphic reflections of the bearing-based instability, become progressively smaller with increasing OISCM angle. However, this advantage at elevated speeds can only be sustained by a corresponding increase in oil-supply pressure to circumvent the advent of a starved inner-film and its attendant imbalance response and thermal growth. In closure, the OISCM bearing is more effective for mitigating rotordynamic instabilities in turborotors than conventional FRBs.

The Volumetric Performance of Cavitating Centrifugal Pumps: Part 2: Predicted and Measured Performance

1986 ◽  
Vol 200 (3) ◽  
pp. 168-172 ◽  
Author(s):  
E Grist
Keyword(s):  
Centrifugal Pump ◽  
Test Data ◽  
Close Agreement ◽  
Engineering Application ◽  
Centrifugal Pumps ◽  
Zone Length ◽  
Temperature Range ◽  
Spherical Cavities ◽  
Performance Comparisons

The predicted performance of a cavitating centrifugal pump, calculated using a method which applies the concept of notional spherical cavities, has been compared with measured performance values. From the close agreement evident in predicting the nett positive suction head at breakdown and the generated head–cavitation zone length curves the method and concept appear suitable for wider engineering application. The volumetric performance comparisons made use test data on water in the temperature range 2–1433°C.

A TRNSYS assisting tool for the estimation of ground thermal properties applied to TRT (thermal response test) data: B2G model

2020 ◽  
pp. 116370
Author(s):  
Antonio Cazorla-Marín ◽  
Carla Montagud-Montalvá ◽  
José Miguel Corberán ◽  
Álvaro Montero ◽  
Teresa Magraner
Keyword(s):  
Thermal Properties ◽  
Test Data ◽  
Thermal Response ◽  
Thermal Response Test ◽  
Response Test

Cavitation in Centrifugal Pumps With Liquids Other Than Water

1961 ◽  
Vol 83 (1) ◽  
pp. 79-89 ◽  
Author(s):  
A. J. Stepanoff
Keyword(s):  
Test Data ◽  
Hot Water ◽  
Centrifugal Pumps ◽  
Specific Speed

Conditions leading to cavitation of liquids other than water are examined. The concept of the thermal cavitation criterion is considered in view of new test data on hot water and other liquids, and its utility for determination of NPSH corrections is demonstrated. The effect of the suction specific speed on the NPSH corrections is tentatively established.

scholarly journals Disturbance Simulation in the Packaging Process of Confectionary Using Virtual Commissioning

Machines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 19
Author(s):  
Johanna Wolf ◽  
Sebastian Carsch ◽  
Clemens Troll ◽  
Jens-Peter Majschak
Keyword(s):  
Machine Learning ◽  
Test Data ◽  
Learning Algorithms ◽  
Machine Learning Algorithms ◽  
Visual Effects ◽  
Computing Power ◽  
Virtual Commissioning ◽  
Sensor Signals ◽  
Assistance Systems ◽  
Sufficient Test

Operator assistance systems can help to reduce disturbance-related machine downtime in food production and packaging processes, especially when combined with machine learning algorithms. These assistance systems analyze the available sensor signals of the process control over time to help operators identify the causes of disturbances. Training such systems requires sufficient test data, which often are hardly available. Thus, this paper presents a study to investigate how test data for teaching machine learning algorithms can be generated by numerical simulation. The potential of using virtual commissioning (VC) software for simulating disturbances of discrete processes is examined, considering the example of a friction and collision-afflicted sub-process from an intermitting wrapping machine for confectionary. In this study the software industrialPhysics (iP) is analyzed regarding accuracy of static and dynamic friction and restitution. The values are verified by setting up virtual substitute tests and comparing the results with analytically determined values. Subsequently, prerecorded disturbances are classified, and seven selected elements are simulated in VC software, recording visual effects and switching the characteristics of sensors. The verification shows that VC software is generally adequate for the assigned task. Restrictions occur regarding the computing power required of the built-in physics engine and the resulting reduction of the machine to be simulated.

Sign in / Sign up

Export Citation Format

Share Document