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Pan J.-Y.,Shenyang Research Institute of Foundry | Liu X.-F.,Shenyang Research Institute of Foundry | He L.-M.,Dalian Deep Blue Pump Co. | Guo X.-L.,Shenyang Research Institute of Foundry | And 2 more authors.
Zhuzao/Foundry | Year: 2012

Silica-base ceramic core is widely used in the investment casting of Ni- and Co-base superalloys below 1550 V. The research status of silica-base ceramic core was reviewed in this paper. Key factors influencing the properties of the ceramic core, such as cristobalite content, mineralizer, granularity and sintering temperature, were presented. Core removal process was also introduced. Source

Zhang M.,Dalian University of Technology | Wang X.,Dalian University of Technology | Xu S.,Dalian University of Technology | Wan X.,Dalian Deep Blue Pump Co.
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2014

To investigate the flexible support of the incompressible seal, negative stiffness characteristic was analyzed. The rotor dynamic coefficients in the neck bush and the ring seal in the LNG pump were predicted by employing three-dimensional flow model, the κ-ε turbulence model and numerically solving the Navier-Stokes equations. The dynamic characteristics were compared in the incompressible seals over a range of rotating speeds and between nominal clearance and twice clearance seals. Through simulating the incompressible flow, as well as analyzing and comparing the circumferential distributions of the pressure and velocity, the reasons for the negative direct stiffness in the uniform annular seal were discovered and the influences on the negative direct stiffness were also found. The results show that: for both the annular seal and the grooved seal, the direct stiffness of twice clearance seal was higher than that of the normal clearance seal, but the cross stiffness of twice clearance seal was smaller than that of the normal clearance seal. It indicated the rotor stability was improved after seal wore. The direct stiffness dropped and the cross stiffness increased with the increase of the rotating speed, which caused rotor stability reduction. In the high rotating speed condition, the annular seal with a small clearance was vulnerable to perform a characteristic of negative stiffness, which destroyed the stability of the rotor system. It is recommended that the grooved seals are applied to the pump to control the incompressible flow against leakage instead of the annular seal. Source

Yuan J.P.,Jiangsu University | Zhu Y.W.,Jiangsu University | Ge A.X.,Dalian Deep Blue Pump Co.
Advanced Materials Research | Year: 2014

Cavitation is one of the most important aspects that need to be considered while designing centrifugal pumps, since it is a major contributor to failure and inefficiency. In order to study the cavitating performance in high-speed centrifugal pumps under low flow rates, the pump named IN-32-32-100 with two different impellers was investigated based on numerical and experimental methods. The impeller case 1 is the impeller with six blades. The impeller case 2 is the impeller with four long and four splitter blades. The research results show that the cavities of two impellers occur at the impeller inlet. The region of developed cavities extends and the volume fraction in the blade passages gradually increases with the decrease of inlet total pressure at the flow rate of 0.5Qd. The cavities distribute asymmetrically in each blade passage and the vapor fraction of one blade passage is significantly larger compared with them of blade passages. The inner flow of the pump can be effectively improved with more uniform pressure distribution by applying splitter blades. The critical cavitation number of the impeller case 1 and impeller case 2 corresponding to the sudden head-drop point are 3.2m and 3.55m, respectively. Compared with impeller case 2, cavitating performance of the pump with impeller case 1 is better. The numerical results agree well with the experimental data, which shows that the numerical method in the present study can to some extent accurately predict the cavitating development inside the high-speed centrifugal pump. © (2014) Trans Tech Publications, Switzerland. Source

Deng D.W.,Dalian University of Technology | Lu J.,Dalian University of Technology | Tian X.,Dalian University of Technology | Tian X.,Shenyang Blower Group | And 2 more authors.
Advanced Materials Research | Year: 2012

The 2Cr13 axle sleeve, used in N52 water pumps, suffered wear after being tested for a relatively short time and fractured when it was beat under the dynamic load. Optical metallographic microscopy, scanning electron microscopy (SEM) and Vickers hardness tester for the fractured 2Cr13 axle sleeve were used to determine the most probable causes of the failure. The results showed that the failure was mainly due to the inappropriate technological parameters of high frequency induction heating and a large amplitude rotor vibration. Meantime, cracks were easily found not only close to the frayed surface but also in the inner part contributed to the inappropriate parameters. Finally, the proper protections were advised to be used for preventing this type of failure for the axle sleeve from happening again in the further. © (2012) Trans Tech Publications, Switzerland. Source

He L.-M.,Dalian Deep Blue Pump Co.
Zhuzao/Foundry | Year: 2011

The structural features and technological requirement of big blade wheel were analyzed, and the normal pressure lost foam casting process of blade wheel as well as the key points should be paid more attention to during the production were discussed. The result indicates that the normal pressure lost foam casting is suitable for production of castings like big warping blade wheel, which are difficult for pattern drawing. Source

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