ZL29滤棒成型机纸盘轮罩变形问题的解决方案

ZL29型滤棒成型机上的纸盘轮罩在用户工厂服役期间极易发生变形。通过变更材质,并试验出一套完善的加工工艺,有效提高了该零件的抗变形能力,并显著提升了外观质量。

汽车变速器盘轮不平衡问题的研究

通过试验对影响盘轮不平衡的2个显著因素--壁厚差值和形状不规进行研究,使用多元线性回归算法对盘轮不平衡量与2个影响显著因素之间的数学模型进行量化分析研究。在此研究基础上,使用去重方法对盘轮进行去重研究,并使用算法求解去重平衡孔个数与去重平衡孔位置。

钢印机

本实用新型为一种在金属板材或型材上压印永久性标志钢印机的革新创造,尤指一种字盘轮具有稳定压力且字盘轮能自动复位的钢印机,它属于无切削金属机械加工设备。该机主要由压紧油缸、字盘轮、纵向导板,纵向滑板,机头机体,液压站。

Effects of the Blade Shape on the Trailing Vortices in Liquid Flow Generated by Disc Turbines

Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their rela-tionship with turbulence properties in a stirred tank of 0.48 m diameter,agitated by four different disc turbines,in-cluding Rushton turbine,concaved blade disk turbine,half elliptical blade disk turbine,and parabolic blade disk turbine.Phase-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in detail.The location,size and strength of vortices were determined by the simplified λ2-criterion and the results showed that the blade shape had great effect on the trailing vortex characteristics.The larger curvature resulted in longer residence time of the vortex at the impeller tip,bigger distance between the upper and lower vortices and longer vortex life,also leads to smaller and stronger vortices.In addition,the turbulent ki-netic energy and turbulent energy dissipation in the discharge flow were determined and discussed.High turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with them.Although restricted to single phase flow,the presented results are essential for reliable de-sign and scale-up of stirred tank with disc turbines.

Mass transfer in gas–liquid stirred reactor with various triple-impeller combinations

The gassed power demand and volumetric mass transfer coefficient （kca） were investigated in a fully baffled, dished-base stirred vessel with a diameter of 0.30 m agitated by five triple-impeller combinations. Six types of impellers （six-half-elliptical-blade disk turbine （HEDT）, four-wide-blade hydrofoil impeller （WH） pumping down （D） and pumping up （U）, parabolic-blade disk turbine （PDT）, and CBY narrow blade （N） and wide blade （W）） were used to form five combinations identified by PDT ＋ 2CBYN, PDT ＋ 2CBYw, PDT ＋ 2WHD, HEDT ＋ 2WHD and HEDT ＋ 2WHo, respectively. The results show that the relative power demand of HEDT ＋ 2WHu is higher than that of other four impeller combinations under all operating conditions. At low superficial gas velocity （uc）, kLa differences among impeller combinations are not obvious. However when UG iS high, PDT ＋ 2WHD shows the best mass transfer performance and HEDT ＋ 2WHu shows the worst mass trans- fer performance under all operating conditions. At high uc and a given power input, the impeller combinations with high agitation speed and big projection cross-sectional area lead to relatively high values of kLa. Based on the experimental data, the regressed correlations of gassed power number with Froude number and gas flow number, and kLa with power consumption and superficial gas velocity are obtained for five different impeller combinations, which could be used as guidance for industrial design.

Effects of reconfiguration on the performance of mobile navigation robot

An irmovative mobile robot that has reconfigurable loeomotion chassis and reconfigurable bionic wheels has been developed to meet the needs of different payload and different terrain. Several prototypes have been achieved by the recortfiguration. By modeling relative comparison coefficients, these prototypes are analyzed in terms of geometrical parameter of trafficability, static stability and maneuverability. The effects of reconfiguration on these indices of robot performance can be compared, i.e. the variable height of chassis h has the biggest effect, the variable length of chassis 1 is the second, then is the camber angle β and the caster angle α. Some principles for reconfiguration are proposed.

ERT Imaging of Gas-Liquid Mixing in Agitated Vessel

An investigation using Electrical Resistance Tomography （ERT） was carried out in order to characterize gas-liquid mixing in an agitated vessel. The experimental work was carried out in a 400 mm diameter agitated vessel that was fitted with four planes, 16 stainless steel electrodes. Agitation was carried out using the Lightnin Labmaster and Rushton turbine while conductivity data acquisition was carried out using the ITS P2000 ERT system. A Mathlab code was developed to construct a surface plot for gas hold-up from the ERT data. Various gas dispersion conditions such as flooded, loaded and fully dispersed were successfully characterized using the ERT technique.

Transient reliability optimization for turbine disk radial deformation

The radial deformation design of turbine disk seriously influences the control of gas turbine high pressure turbine(HPT) blade-tip radial running clearance(BTRRC). To improve the design of BTRRC under continuous operation, the nonlinear dynamic reliability optimization of disk radial deformation was implemented based on extremum response surface method(ERSM), including ERSM-based quadratic function(QF-ERSM) and ERSM-based support vector machine of regression(SR-ERSM). The mathematical models of the two methods were established and the framework of reliability-based dynamic design optimization was developed. The numerical experiments demonstrate that the proposed optimization methods have the promising potential in reducing additional design samples and improving computational efficiency with acceptable precision, in which the SR-ERSM emerges more obviously. Through the case study, we find that disk radial deformation is reduced by about 6.5×10–5 m; δ=1.31×10–3 m is optimal for turbine disk radial deformation design and the proposed methods are verified again. The presented efforts provide an effective optimization method for the nonlinear transient design of motion structures for further research, and enrich mechanical reliability design theory.

Research on reliability of turbine disk with random structure

Structure of a rotor and other design parameters are all viewed as constant using finite element software to analyze reliability of the rotor. In this case,reliability analysis of the rotor can't be realized for design parameters as random. Based on theory of elastic mechanics,starting with the micro element of the rotor,stress formulas on arbitrary point of turbine disc with equal and variable thickness are deducted under the influence of centrifugal force and temperature field on rotor system simultaneously. Considering the random of structural size of the turbine rotor,temperature stress,rotating speed,external loads and material strength,the reliability of a rotor is studied with stress-strength interference model,integral stochastic finite element method(ISFEM) and Gram-Charlier series method,and random structural reliability of the rotor is computed with higher accuracy.

太和殿珐琅仙鹤年代考析

金碧辉煌的太和殿中央有一高2米多的高台,台上设有镂空金漆蟠龙宝座,宝座周围摆放着角端、香筒、仙鹤、鼎式炉等铜胎珐琅制品,更增添了太和殿富丽威严的氛围。 笔者有幸于1992年10月对这些珐琅器进行清洗修复,使其再现当年风采。尤其是那对体态高大秀逸的珐琅仙鹤,脱俗出尘,亭亭玉立,造型极为优美。(图一)这对仙鹤通高1.68米(不含木座),鹤顶椭圆形,暗红色釉,为5毫米宽金环所环绕。

受潮磁带的修理

经过频繁使用或长期存放,盒式磁带尤其是国产带,容易受潮。故障现象为带速减慢,声音走调,影响使用效果,甚至无法使用。我们在受潮磁带修理中,经过多次试验,将受潮磁带连带盘轮移装到报废的日产原带的塑料盒内,取得良好效果。目前使用的国产带和日产原带,结构基本相同。塑料盒内封装磁带,两个带盘轮和两张双孔垫片。不同的是国产带的双孔垫片是浸渍石墨的牛皮纸,而日产原带的双孔垫片则是聚四氟乙烯塑料簿片,浸渍石墨而成。由于纸质垫片容易受潮膨胀,使磁带与塑料盒的间隙减小,磁带走动擦碰垫片,产生阻力,致使带速减慢。我们在修理受潮磁带过程中,经常发现纸质垫片上有明显的擦痕,这表明纸质垫片受潮后成为磁带运行的阻力源。而塑料簿片不易受潮,故日产原带的受潮故障较少。除垫片质的不同外,垫片的形状大小也各异。国产带的垫片为9.6×4.6厘米,垫片上有20个凹凸压印。凸面隆起形成高泡,面向磁带。这些高泡,在其垫片受潮膨胀后与运行的磁带相摩擦。而日产原带的垫片9.7×2.8厘米。

Numerical Investigation of Flutter Stability in Subsonic Space Turbine Blisk with Emphasis on Cut-on/Cut-off Modes and Interblade Phase Angles

The so-called blisks,i.e.integrally bladed disks,are characterized by very low viscous material damping and make the flutter prediction much more critical.In that framework,a two-dimensional numerical study of a space turbine blisk featuring complex deformation of blades and high eigenfrequency(>40kHz)is performed.The simulations are based on unsteady Reynolds Averaged Navier Stokes computations linearized in the frequency domain and consist in the superposition of an unsteady linear(in time)pressure field,generated by a harmonic perturbation,upon a steady nonlinear(in space)flow.The aerodynamic damping coefficient is calculated over a range of nodal diameters,and the blades are predicted aeroelastically stable.However,violent changes occur and are rather critical since sudden and large deviations in stability appear.In that context,the nature of the waves propagating from the cascade are evaluated.Such an approach provides fundamental knowledge about the perturbations which can either propagate to the far-field(cut-on mode)or decay(cut-off mode).It is expected that the ability of the flow to damp or to amplify the blade motion is strongly affected by the way unsteady perturbations are transferred from the cascade to the far-field.The nature of the waves are first assessed from the aforementioned linearized results,then they are evaluated analytically and finally compared.A good agreement is found despite the strong assumptions of the analytical model.The results show a clear correlation between the cut-on/cut-off conditions and stability.The least stable configuration corresponds to cut-off mode at the inlet and no wave at the outlet.Without outgoing waves from the cascade,the blade is prone to be less stable:the energy from the blades vibration is necessarily dissipated or sent out by the cascade.

Numerical investigation of disc heat transfer with a novel fin-like structure

Rotary disc is a key part in aero engine, HPT rotor disc due to its highest thermal load as well as mechanical load, always suffers from thermal or mechanical failure. In this paper, the authors initiate a new kind of novel fin-like structure which is presented on both surfaces of the rotating disc. The presence of the fin-like structure acts like a turbulence & vortex generator and hence increases the heat transfer effectiveness between the cooler cavity flow and the higher temperature disc surface. This paper deals with a numerical investigation of the new kind of fin-like structure which is tending to be applied on the high pressure turbine rotor's rotating disc. Numerical results revealed that with this novel structure thermal load of the disc reduced noticeably ranging from 10℃ to 20℃. This can be explained by the vortex structure generated by the disturbance of the cavity's cooling flow, thus enhancing the convective heat transfer rates between the disc surface and the cavity flow.