Numerical Assessment of Cavitation Erosion Risk in a Commercial Water-Jet Pump

2021 ◽  
Author(s):  
Mohammad Hossein Arabnejad ◽  
Urban Svennberg ◽  
Rickard E. Bensow
Keyword(s):  
Cavitation Erosion ◽  
Assessment Method ◽  
Water Jet ◽  
Numerical Results ◽  
Jet Pump ◽  
Erosion Risk ◽  
Hydraulic Machines ◽  
Numerical Assessment ◽  
Risk Areas ◽  
The Difference

Abstract In this paper, the risk of cavitation erosion is assessed in a commercial water-jet pump using a recently developed numerical erosion assessment method by Arabnejad et al. [1]. This assessment is performed for two flow conditions with different cavitation erosion risk according to the experimental paint tests and the high erosion risk areas identified by the method are compared with the experimental results. This comparison shows that the applied method is capable of both identifying the regions of high erosion risk and also capturing the difference between the cavitation erosion risk in the two studied conditions. The latter capability of the numerical assessment method, which has not been reported in the literature for other published methods, is one step forward toward the application of the method in the design process of hydraulic machines. Furthermore, the numerical results are analysed to explain the reasons for different erosion risk in the two conditions. This analysis reveals that this difference is mostly related to the stronger flow non-uniformities entering the rotor in the most erosive condition. Using the numerical results, one reason behind these stronger nonuniformities is identified to be the stronger bursting of vortices shed from the shaft in the most erosive condition.

scholarly journals Assessment of Cavitation Erosion in a Water-Jet Pump Based on the Erosive Power Method

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ning Qiu ◽  
Han Zhu ◽  
Yun Long ◽  
Jinqing Zhong ◽  
Rongsheng Zhu ◽  
...  
Keyword(s):  
Cavitation Erosion ◽  
Water Jet ◽  
Power Method ◽  
Jet Pump ◽  
Tip Leakage ◽  
Long Duration ◽  
Simulation Based ◽  
Jet Pumps ◽  
Sst Turbulence Model ◽  
Simulation Error

Cavitation affects the performance of water-jet pumps. Cavitation erosion will appear on the surface of the blade under long-duration cavitation conditions. The cavitation evolution under specific working conditions was simulated and analyzed. The erosive power method based on the theory of macroscopic cavitation was used to predict cavitation erosion. The result shows that the head of the water-jet pump calculated using the DCM-SST turbulence model is 12.48 m. The simulation error of the rated head is 3.8%. The cavitation structure of tip leakage vortex was better captured. With the decrease of the net positive suction head, the position where the severe cavitation appears in the impeller domain gradually moves from the tip to the root. The erosion region obtained by the cavitation simulation based on the erosive power method is similar to the practical erosion profile in engineering. As the net positive suction head decreases, the erodible area becomes larger, and the erosion intensity increases.

scholarly journals Assessment of Spatial Soil Erosion Susceptibility Based on the CORINE Model in the Gumara-Maksegnit Watershed, Ethiopia

2018 ◽  
Vol 8 ◽  
pp. 38-45
Author(s):  
Kassaye Gurebiyaw ◽  
Hailu Kendie Addis ◽  
Achenafi Teklay
Keyword(s):  
Soil Erosion ◽  
Land Cover ◽  
Water Conservation ◽  
Assessment Method ◽  
Low Risk ◽  
Risk Map ◽  
Moderate Risk ◽  
Erosion Risk ◽  
Soil Erosion Risk ◽  
Risk Areas

Soil erosion is one of the major environmental threats in the northwestern Amhara Region of Ethiopia. The objective of this study is to assess the spatial heterogeneity of soil erosion risk within the Gumara-Maksegnit watershed (57.3 km2) using the Coordination of Information on the Environment (CORINE) soil erosion assessment method to determine the most endangered areas. The model is simple and robust and consists of six steps overlaying combinations of soil texture, depth, stoniness, climatic and land-use/land-cover information with GIS support. The CORINE model was used to produce potential and actual soil erosion maps. The potential soil erosion map consists of the erosion risk of the land without considering current vegetation, but can be expanded to consider current land cover. The potential soil erosion risk map showed that a small part of the watershed (6.63 %) had low risk, 17.92 % had moderate risk and a large part of the study area (75.45 %) had high potential erosion risk. Meanwhile, the actual soil erosion risk map showed that a small part of the watershed (11.92 %) had low risk, 20.85 % of the area had moderate risk, and a large part of the study area (67.23 %) had high actual soil erosion risk. Low soil erosion risk areas were located in the southern part of the watershed, high erosion risk areas were found in the northern, northwestern and eastern part of the watershed, while moderately risky areas were randomly distributed throughout the watershed. Overall, the CORINE model can play a role in soil and water conservation by identifying highly endangered areas.

scholarly journals Numerical assessment of cavitation erosion risk using incompressible simulation of cavitating flows

Wear ◽  
2021 ◽  
Vol 464-465 ◽  
pp. 203529 ◽  
Author(s):  
Mohammad Hossein Arabnejad ◽  
Urban Svennberg ◽  
Rickard E. Bensow
Keyword(s):  
Cavitation Erosion ◽  
Cavitating Flows ◽  
Erosion Risk ◽  
Numerical Assessment

Experimental and Numerical Study on Grinding Temperature during Surface Grinding with Different Cooling Methods

2009 ◽  
Vol 416 ◽  
pp. 514-518 ◽  
Author(s):  
Qing Long An ◽  
Yu Can Fu ◽  
Jiu Hua Xu
Keyword(s):  
Numerical Study ◽  
Specific Energy Consumption ◽  
Ground Surface ◽  
Numerical Results ◽  
Surface Grinding ◽  
Grinding Temperature ◽  
Air Jet ◽  
The Difference ◽  
High Specific Energy ◽  
Cooling Methods

Grinding, characterized by its high specific energy consumption, may generate high grinding zone temperature. These can cause thermal damage to the ground surface and poor surface integrity, especially in the grinding of difficult-to-machine materials. In this paper, experimental and fem study on grinding temperature during surface grinding of Ti-6Al-4V with different cooling methods. A comparison between the experimental and numerical results is made. It is indicated that the difference between experimental and numerical results is below 15% and the numerical results can be considered reliable. Grinding temperature can be more effectively reduced with CPMJ than that with cold air jet and flood cooling method.

Numerical assessment of pulsating water jet in the conical diffusers

2017 ◽  
Author(s):  
Constantin Tanasa ◽  
Tiberiu Ciocan ◽  
Sebastian Muntean
Keyword(s):  
Water Jet ◽  
Numerical Assessment ◽  
Pulsating Water Jet

CFD Calculation of the Flow Through a Water-Jet Pump

2001 ◽  
Author(s):  
Peixin Hu ◽  
◽  
M Zangeneh ◽  
Keyword(s):  
Water Jet ◽  
Jet Pump ◽  
Flow Through

Analysis of Stresses in CFRP Composite Plates Drilled with Conventional and Abrasive Water Jet Machining

2013 ◽  
Vol 763 ◽  
pp. 127-143 ◽  
Author(s):  
M. Saleem ◽  
Habiba Bougherara ◽  
L. Toubal ◽  
F. Cénac ◽  
Redouane Zitoune
Keyword(s):  
Fatigue Testing ◽  
Composite Plates ◽  
Water Jet ◽  
Image Correlation ◽  
Initial Surface ◽  
Abrasive Water Jet ◽  
Machining Processes ◽  
Static Tests ◽  
The Difference ◽  
Conventional Machining

The aim of this paper is to analyze the influence of two machining processes on the mechanical behaviour of composite plates under cyclic loading. For this purpose, an experimental study using several CFRP plates drilled with conventional machining and non-conventional machining (abrasive water jet) was carried out. Digital image correlation and static tests using an Instron 4206 tester were performed. In addition, infrared thermography (IR) and fatigue tests were also performed to assess temperature and damage evolutions and also the stiffness degradation. Fatigue results have shown that the damage accumulation in specimens drilled with conventional machining was higher than the abrasive water jet ones. Furthermore, the endurance limit for plates drilled conventionally was approximately 10% higher than those drilled with abrasive water jet. This difference was related to the initial surface integrity after machining induced by the difference in the mechanism of material's removal between the two processes. The difference in surface texture was responsible for the initiation of stress concentration sites as evident from IR camera’s stress analysis. This was confirmed by SEM tests conducted after a destructive sectioning of the specimens before fatigue testing.

NUMERICAL REEXAMINATION OF SUPERSYMMETRIC AND NONSUPERSYMMETRIC SU(5)-LIKE GRAND UNIFIED MODELS

1989 ◽  
Vol 04 (10) ◽  
pp. 2531-2559 ◽  
Author(s):  
DARIUSZ K. GRECH
Keyword(s):  
Numerical Analysis ◽  
Numerical Computation ◽  
Numerical Results ◽  
Yukawa Couplings ◽  
Loop Level ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Supersymmetric Particles ◽  
The Difference

The significance of numerical analysis in both nonsupersymmetric and supersymmetric Grand Unified Theories is pointed out. The exact analytical and numerical analysis we present shows a need of larger corrections to the values of unifying parameters, i.e. sin 2 θw, Mx, τp than those often quoted in literature. When an unmodified nonsupersymmetric version of SU(5) is considered we show that numerical computation allows some of the models still to be experimentally admissible. The difference between analytical and numerical results for the supersymmetric SU(5) model is also stressed. In particular, corrections due to the mass threshold of additional generations or supersymmetric particles are calculated both analytically and numerically at the two-loop level. We found them far more important for the final values of sin 2 θw, Mx and τp than the effects of Higgs-Yukawa couplings between scalars and fermions.

scholarly journals Assessment of Soil Erosion and Its Impact on Agricultural Productivity by Using the RMMF Model and Local Perception: A Case Study of Rangun Watershed of Mid-Hills, Nepal

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Dinesh Bhandari ◽  
Rajeev Joshi ◽  
Raju Raj Regmi ◽  
Nripesh Awasthi
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Group Discussion ◽  
Agricultural Productivity ◽  
Weighted Mean ◽  
Risk Area ◽  
Barren Land ◽  
Erosion Risk ◽  
Risk Areas ◽  
The Impact

Soil erosion is a major concern for the environment and natural resources leading to a serious threat to agricultural productivity and one of the major causes of land degradation in the mid-hills region of Nepal. An accurate assessment of soil erosion is needed to reduce the problem of soil loss in highly fragile mountainous areas. The present study aimed to assess spatial soil loss rate and identified risk areas and their perceived impact on agricultural productivity by using the Revised Morgan–Morgan–Finney (RMMF) model and social survey in the Rangun watershed of Dadeldhura district, Nepal. Soil erosion was assessed by using data on soil, digital elevation model, rainfall, land use, and land cover visually interpreted from multitemporal satellite images, and ILWIS 3.3 academic software was used to perform the model. A household questionnaire survey (n = 120) and focus group discussion (n = 2) in identified risk areas were carried out to understand the people’s perception towards soil erosion and its impact on agricultural productivity. The predicted average soil erosions from the forest, agriculture, and barren land were 2.7 t ha−1 yr−1, 53.73 t ha−1 yr−1, and 462.59 t ha−1 yr−1, respectively. The erosion risk area under very low to low, moderate to moderately high, and high to very high covers 92.32%, 4.96%, and 2.73%, respectively. It indicates that the rate of soil erosion was lower in forest areas, whereas it was higher in the barren land. The cropped area of the watershed has been reduced by 2.96 ha−1 yr−1, and productivity has been decreased by 0.238 t ha−1 yr−1. The impacts such as removal of topsoil (weighted mean = 4.19) and gully formation (weighted mean = 3.56) were the highest perceived factors causing productivity decline due to erosion. People perceived the impact of erosion in agricultural productivity differently ( ∗ significant at P ≤ 0.05 ). The study concluded that, comparatively, barren and agricultural lands seem more susceptible to erosion, so the long-term conservation and management investment in susceptible areas for restoration, protection, and socioeconomic support contribute significantly to land rehabilitation in the Rangun watershed.

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