Papers by Keyword: Impeller

Abstract: Thus far, axial flow pumps remain a significant hydrodynamic unit. These pumps have common applications for various systems that require a high flow rate and a lower head. They tend to be less efficient and consume excessive power when operating at low flow conditions. Most of the studies focus on improving the hydraulic performance of these pumps based on the best efficiency point (BEP) flow conditions. This approach is mostly based on the assumption that the pump will always operate at BEP. However, this is not always the case, because the operational condition of the pump may require an adjustment to meet certain system demands. Hence, it is necessary to emphasize the need to improve the hydraulic performance of these pumps for multiple flow conditions. This means that in addition to BEP, the lowest, and the highest operational conditions need to be considered when improving the pump performance. Also, it is important to review the phenomenon of cavitation in every design optimization investigation, given its significance to pump performance and some misrepresentation which are sometimes associated with its assessment. Therefore. the main contribution of this article is to briefly discuss the successful and unsuccessful design optimization methods of an axial flow pump. Furthermore, it highlights the significance of improving the pump performance at multiple flow conditions and also to incorporate the analysis of using CFD methods to analyze the results of cavitation performance in every pump performance improvement investigation.

Abstract: While an intermediate treatment contractor of construction waste extracts renewable fuels from construction wastes, water is stored in a water tank and a considerable amount of sludge remain in the water. In this respect, the present study designed an apparatus to automatically discharge sludge from the water tank. The discharging process of the apparatus is as follows: it sucks sludge along with water of the water tank into a storage tank. Sludge and water stay for a certain time period until the former settles. And water drains out from the storage tank, being separated from sludge that still remains in the storage tank. The amount of sludge to discharge depends on its storage time in the tank. Therefore, the duration of settlement was measured to find an optimal time. Discharging test was repeated. An impeller was installed on top of the storage tank to know how it affects sludge settlement. Using the collected data, this study confirmed the factors necessary for smooth discharging of sludge.

Abstract: The grinding of riblets with multiple profiled grinding wheels is an efficient method to minimize the fluid friction on surfaces. In turbo machinery components, like pump impellers or compressor blades, the riblets must be ground with a curved tool path since the flow is rarely linear on such surfaces. This leads to angular errors in the generated riblet profiles and therefore requires the use of grinding wheels with smaller diameters. The tool wear increases due to lateral strain on the peaks of the grinding wheel. Consequently, the increased wear and the need of smaller tool diameters decrease the efficiency of the process. In this paper a structuring process with dicing blades was investigated in order to increase the economic viability of this process. A dressing operation for such tools is not necessary and thus reduces the non-productive time of the manufacturing process. Furthermore, profile tip wear has no negative effects on the aspect ratio of the generated riblets since the riblet geometry is determined by the thickness of the dicing blades.

Abstract: The semi-solid casting process has a lot of advantages in controlling casting defects. High quality impellers have been produced successfully by the semi-solid process for several years. The semi-solid processed impellers have uniform microstructure and premier mechanical properties, and therefore excellent durability. Further improvement of performance of the impellers is demanded and achieved by increasing curvature and length of blades of impellers. These changes create potential trend of casting defects in blades of impellers, such as non-filling holes. In our recently work, castings were made in different conditions, including two-step plunger velocity and one-step plunger velocity. The experimental results show that the change of plunger velocity played a decisive role in the forming of non-filling holes. Entrapped gas is the direct reason of the non-filling holes. With the increasing of plunger velocity, the area of non-filling holes increased. The non-filling holes in blades could be avoided by eliminating the plunger velocity’s changing during filling blades.

Abstract: This paper deals with a comparative study of the outlet pressure-energy between a conventional and normal blade impeller and an airfoil-shaped blade impeller of a centrifugal pump. Although the volute casing is an important component along with an impeller [1], the present comparative analysis makes the volute casing redundant to the study, hence neglected. All centrifugal pumps are usually designed and manufactured using backward swept blades with equal camber on the top and bottom sides. An increased camber on the top side is an ideal trait for a lift generating airfoil. The purpose is to implement the principle of lift generation of airfoil for centrifugal pumps. As a result, a local suction side and pressure side can be visualized using CFX-post processor. The 3D analysis of such a centrifugal pump impeller is designed in SOLIDWORKS® and analyzed using ANSYS® CFX. The SST (Menter’s Shear Stress Transport) model is used as it combines both the k-ω and k-ε turbulence models.

Abstract: The paper presents the analytical solution used to calculate the depression which appears under different types of impellers. This solution can be useful as a preliminary calculus to estimate the magnitude of the depression created at different rotational speeds, in order not to damage the equipment from different systems, such as hydraulic turbines. The authors obtain the variable radius of the depression zone, the pressure inside the depression zone and the depression height. The theoretical approach, the calculus itself and the numerical results presented in the article are original. In order to validate the proposed calculus, experiments were carried out using two experimental setups. The performed measurements showed a good agreement of the experimental and theoretical results.

Abstract: In order to improve the efficiency of centrifugal pump, based on the bionics principle, established non-smooth surfaces of various groove structure on the centrifugal pump impeller. The internal flow field of it was numerically simulated through RNG k-ε turbulence model. Research the drag reduction characteristics of non-smooth impeller in different groove shape and arrangement. The results showed that the biggest drag reduction rate of centrifugal pump with non-smooth blades is about 6.22%. The blades of non-smooth unit can effectively inhibit the near wall boundary layer flow state, reduce the shear stress on blades wall, reduce the internal fluid turbulent degree of centrifugal pump, so that the fluid flow in centrifugal pump impeller is more stable, improve the efficiency of centrifugal pump.

Abstract: The performance of blower depends on impeller condition. This paper is to discuss the open face impeller condition related to performance based on performance curve provided by the manufacturer. The impeller condition is observed under three different conditions. The first condition is that the impeller area is covered by 3 mm thick of fouling. The second condition is that there is a 1 mm of rubbing on the vane and the third condition is the impeller after being repaired. The datas are taken by the actual operation condition. The observed data is then calculated and plotted on OEM performance curve. The result shows that the first condition has the lowest performance; the produced head is 47% lower than the OEM’s.

Abstract: It’s necessary to calculate and analyze the strength of the pump impeller for the safe operation of the pump. In this paper, the impeller strength of a two-way full-adjust horizontal axial-flow pump in a domestic pump station under forward pumping conditions was calculated by using the unidirectional fluid-structure interaction method; it means loading the blade surface water pressure calculating from CFD software CFX as structure surface loads to the blade, and then calculating the strength of the impeller using finite element software ANSYS ; the strength of the impeller was calculated under different blade rotating angle conditions. Through the calculation, we has got static stress and deformation distribution in the impeller. The results show that under each blade rotating angle, the maximum static stress always increases with lift increasing; the maximum static stress occurs at the junction of the blade and hub; the stress concentration also occurs in there prone to cause fatigue failure; maximum deformation of the blade occurs in the leading edge close to the rim; the maximum static stress is far less than yield strength of the material that the static stress can not cause cracks.

Abstract: Processing any kind of parts, requires in our days a focus on obtaining, not only the required characteristics, but a high economic efficiency too. One of the main ways to reduce costs is to reduce processing duration. Starting from profiled turning rotors made by difficult-to-cut materials such as titanium alloys or materials with nickel base, paper analyze the efficiency of processing taking into account all types of inserts available to be used for a given toolholder type. The analysis highlights certain processing features according to the geometric shape and makes a classification based on these performances. The verification of these features is performed with a CAD program on an impeller, using machining characteristics declared by the chosen manufacturer, considering the linear zig method for turning. Regarding the contour turning method, it makes an analysis of the problems caused by the variation of chip length, relative to the maximum cutting depth allowed by tool.