Numerical and Experimental Study of Hydraulic Performance and Wear Characteristics of a Slurry Pump

The slurry pump is widely used in ore mining, metal smelting, petrochemical, and other industries, mainly to transport fluid media containing large solid particles. Importantly, it is easy to damage the impeller of a slurry pump in the operation process, which greatly affects the performance of the pump. In this paper, a 25 MZ slurry pump was selected as the research object, and the Euler–Euler multiphase flow model was employed to analyze the internal flow characteristics of the slurry pump under the conditions of clear water and solid–liquid two-phase flow. Additionally, the flow characteristics of each part under different flow conditions were studied, and the effects of different particle volume concentrations, particle sizes, and pump speeds on the impeller’s wear characteristics and hydraulic performance were analyzed. In order to verify the reliability and accuracy of the numerical simulation results, clean water and solid–liquid two-phase flow wear tests of the slurry pump were carried out, and the results showed that a high solid volume fraction and solid–phase slip velocity were generated at the junction of the blade leading edge and the rear cover plate, thus leading to easier wear of the blade. Therefore, enhancing the strength of the junction between the blade leading edge and the rear cover plate is beneficial for improving service life and should be considered in the design of slurry pumps.

Comparison between double slope solar still and fourfold slope solar still: energy, exergy, exergoeconomic, and enviroeconomic evaluation

This paper proposes a single basin fourfold slope solar still, which includes a fourfold slope glass cover plate used for solar heat collection and steam condensation. In order to show the efficiency of fourfold slope solar still, comparative experiments are conducted under the winter climate conditions in Hangzhou for testing the operational performance of double slope type solar still (DOSS) and fourfold slope still (FOSS), so as to make a comparative analysis between them. Results show that the productivity of fourfold slope still is 19.51% higher than that of double slope still, and fourfold slope solar still enhances the average hourly energy efficiency by 31.11%. According to the energy method, the energy payback time values of fourfold slope solar still and double slope solar still are 64.88 months and 75.42 months respectively. According to the environmental parameter method, FOSS and DOSS reduce 5.47 tons and 4.58 tons of CO2 respectively. The corresponding values based on the exergy environment parameters are 0.21 and 0.18 tons of CO2, respectively. The fourfold slope solar still has more obvious emission reduction function than the double slope solar still. The cost of distilled water of fourfold slope solar still is 0.28 RMB/kg, and the cost of double slope solar still is 0.30 RMB/kg. In addition, the environmental and economic parameters of fourfold slope still and double slope still are 79.29$ (561.37RMB) and 66.35$ (469.76RMB), respectively. While, the corresponding values based on the exergoenvironmental parameter are 3.05$ (21.59RMB) and 2.56$ (18.12RMB), respectively. From the analysis of exergoeconomic and exergoenvironmental parameters, fourfold slope single basin solar still appears to be more effective.

Reinforcement of steel beam-to-double column moment connection using side plates

One of the disadvantages of conventional steel structures in Iran is the common way of I-shaped beam to double column fixed connection that do not perform well against seismic loads. This article uses the side plate to modify and optimize the connection. Using this new geometry, the beam-to-column direct connection is eliminated, and there is no longer any concern about the brittle fracture of penetration weld of the beam-to-column connection and the weakness of panel zone that occur in the common fixed connections. In addition, by eliminating the direct transfer of beam flange force to the double column connection plate, the problem of deformation, complexity or buckling of the cover plate of the column is spontaneously removed. In this paper, in order to investigate the nonlinear behavior of beam-to-double column connection system, a number of three-dimensional finite element models under the effect of cyclic loading have been analyzed. The results show that the beam-to-double column connection using the side plates has good strength and ductility and can be used in special moment frames for seismic areas.

Research on the hysteretic performance of flower-gusset composite joints for single-layer aluminium alloy lattice shell structures

Joints are the most critical component of reticulated shell structures, and their hysteretic performance is crucial to the mechanical properties of the whole reticulated shell structure under seismic action. Therefore, the hysteretic behaviour of aluminium alloy flower-gusset composite joint for an out-of-plane bending moment was studied by experiments and numerical analysis. The results show that the hysteretic curves of flower-gusset composite joints and gusset joints contain four stages: an elastic stage, a bolt slip stage, a hole wall pressure-stiffness degradation stage and a failure stage. The hysteretic performance of the new flower-gusset composite joint is obviously better than that of the traditional plate joint. With the increase in the thickness of the cover plate, the bending stiffness of the flower-gusset composite joint increases significantly, while the rotational deformation decreases. Then, a restoring force model of the flower-gusset composite joint is proposed through theoretical analysis based on experiments and numerical analysis.

Improvement of Mechanical Properties and Forming Efficiency during Hot Gas Forming of CFRP Curved Surface Components

Carbon fiber reinforced plastics (CFRP) are widely used in aerospace and new energy vehicles due to their high specific strength and flexible design ability. At present, the traditional forming process of CFRP curved surface components has problems of low mechanical properties and long processing time. In this paper, a new method of hot gas forming was proposed to obtain CFRP components. By applying high temperature and high-pressure gas on one side of CFRP, the material was forced to deform and solidify at the same time. A special device for hot gas forming was designed and developed. The curing behavior and mechanical properties of original CFRP plates were studied. The main defects and the corresponding control methods of hot gas forming parts were analyzed by forming spherical parts, and the feasibility of the hot gas forming process was verified. Taking the battery cover plate of a new energy vehicle as the research object, the influence of forming temperature, gas pressure, pressurization rate and other process parameters on the mechanical properties of complex CFRP components were analyzed. The mechanism of both strength and efficiency improvement was analyzed. The results showed that with the increasing of gas pressure, the tensile strength and forming efficiency of the CFRP curved components were improved obviously. Under reasonable forming parameters, the tensile strength of the obtained parts was increased by 37%, and the forming efficiency was increased by 58%. The fiber bundles were distributed more evenly and compactly under the hot gas forming. This showed that the use of hot gas forming had good potential in the preparation of high-performance CFRP parts, which was helpful to improve the processing efficiency and forming quality of CFRP curved parts in the aerospace and new energy automotive fields.

803 Management of An Intra-Oral Resection with Integra® Dermal Regeneration Template – Worth A Bite?

Introduction There are a spectrum of treatment options available for reconstruction of oral mucosal defects including secondary healing, skin grafts, local flaps and microvascular free flaps. We present the use of an alternative intra-oral reconstruction with Integra® Dermal Regeneration Template. Case Report An 85-year-old patient with a severe gag reflex and history of oral cancer presented with biopsy proven severe dysplasia of the right palate extending to the hamular notch. She was treated with wide local excision, extraction of teeth, buccal fat pad advancement for closure of an oral-antral communication and placement of Integra® Dermal Regeneration Template. Discharge was possible the same day as the patient was able to eat and had minimal pain. Discussion Integra® Dermal Regeneration Template is a bilayer wound matrix consisting of silicone in the outer layer with bovine collagen and glycosaminoglycan from shark cartilage in the inner layer. Oral cancer predominantly affects the older population, and this method can reduce surgical time, remove donor site pain, reduce post-operative pain and avoid use of a cover plate where a strong gag reflex was present. The area heals quickly and aids quick restoration of oral function. Conclusion Integra® Dermal Regeneration Template has been used for head and neck defects with good outcomes. It is being increasingly used intra-orally with good outcomes, suggesting a further application of the material with advantages over traditional techniques in specific patient groups.