Gas film lubrication method on rotation shaft seal based on contact design

Purpose Wear failure happens frequently in rubber seal of high-speed rotating shaft because of the dry friction. Some traditional lubrication methods are not effective because of the restrictions on the relative high speed, temperature and others. This paper aims to present a new method of lubrication with gas film for the rotation shaft seal based on the contact design. Design/methodology/approach To obtain the generation condition of gas film and good effect of lubrication in the contact gap between the shaft and its seal, a series of micro-spiral grooves are designed on the contact surface of rubber seal so as to obtain a continuous dynamic pressure difference. Findings The result is that the distribution of the gas film in the micro-gap is continuous under the design of the spiral grooves and the contact with eccentricity because of the deformation of rubber seal, which is verified through the simulation calculation and experiment test. It is confirmed that the lubrication method with gas film through designing micro-spiral grooves on the contact surface is effective, and can achieve self-adaptive air lubrication for the high-speed shaft under the premise of the reliable sealing. Originality/value The method of gas film lubrication is realized through designing a microstructure of spiral grooves on the rubber surface to change the contact status, which can form a mechanism of adaptive lubrication to reduce the dry friction automatically in the contact gap. For the cross-scale difference between the rubber seal and gas film, a new modeling method is presented by building the mapping relation for the split blocks and repairing technique with integrated computer engineering and manufacturing, to reduce the possibility of nonconvergence and improve the efficiency and accuracy of calculation.

Ferrofluid Lubrication of Optimized Spiral-Grooved Conical Hybrid Journal Bearing using Current Carrying Wire Model

In order to systematically investigate the behaviour of fluid-film bearing, the determination of optimal parameters is of utmost importance. The core contributions of this paper are (1) modeling of the conical bearing for spiral-grooves with ferrofluid lubrication using current carrying wire model for fixed coordinate system, (2) deriving the expressions for magnetic field model and frictional power loss other than Reynolds equation for ferrofluid lubrication, and (3) evaluation of optimal values of spiral-grooved bearing surface for different cross-sectional shapes and that of current carrying wire model for magnetic field generation in ferrofluid lubrication. Generalized Minimum RESidual iterative solver and Newton-Raphson method has facilitated the solution of complex non-linear Finite Element (FE) formulated governing equations. Initially, the results have been obtained for determining the optimal values of spiral-groove and ferrofluid model attributes. After that, using these optimal values, corresponding performance indicators are evaluated. It was found that there exists a optimum value of different geometric features for distinct cross-sectional shapes of spiral-grooves.

Experimental measurements of the thermo elastic behavior of a dry gas seal operating with logarithmic spiral grooves of 11° and 15°

This work shows the experimental thermo elastic behavior of the stationary ring of a dry gas seal with logarithmic spiral grooves of 15° (common commercial configuration) and 11° spiral (configuration evaluated to confirm analytical predictions developed on previous works), as well as the hydrodynamic pressure of the fluid film. The stationary ring temperature is obtained through an array of sensors embedded in the ring and the ring deformation, resulting from the thermal and mechanical load, is collected by two strain gages. The hydrodynamic pressure produced in the fluid film is measured using dynamic pressure sensors. Two novel instrumentation methods are defined to collect the ring deformation and the dynamic pressure of the seal. The results show that the seal with spiral grooves of 11° at low speed presents a temperature increment induced by the contact between the rings; this contact may induce the premature fault of the rings, so that the 11° spiral seal needs more speed than the spiral of 15° to enter a hydrodynamic lubrication regime. The experiments show that the stationary ring distortion is induced by the temperature gradient and by the hydrostatic and hydrodynamic pressure; however, the thermal distortion of the ring is dominant for the current experimental conditions. The ring’s axial distortion also affects the seal static and dynamic performance due to the modification of the hydrodynamic regime.

ST41 Tensile Strength Analysis of Spiral Groove Welding with Three Current Variations

Welding is one of the important aspects in the process of joining metal, iron or steel. This study aims to determine the effect of SMAW welding techniques in spiral grooves with variations in currents of 100 Amperes, 110 Amperes and 120 Amperes to the tensile strength of St 41 steel. This research is an experimental study conducted in two places namely BLKI Singosari, Malang and Faculty of Engineering, ITN Malang, East Java. The results showed that the current strength and electrode flow in welding have an influence on the tensile strength even though the results are not significant. Average tensile strength at 100 Amperes current is 46.75 Kgf / mm², at 110 Amperes current is 44.87 Kgf / mm², and at 120 Amperes current is 43.80 Kgf / mm². The results of this test indicate that the variation of the current in SMAW welding with the spiral groove method influences the tensile strength of St 41 steel. Based on the findings in this study it can be concluded that the highest tensile strength value of 46.75 Kgf / mm² occurs in welding spiral grooves with strong currents of 100 Ampere. Keywords : SMAW welding; spiral groove, strong current, tensile strength; ST41.ReferencesAnwar, B. (2017). Analisis kekuatan tarik hasil pengelasan posisi bawah tangan dengan perbedaan variasi kuat arus listrik pada baja st 42. Teknologi, 16 (1), 18-24.Budiman, H. (2016). Analisis pengujian tarik (tensile test) pada baja st37 dengan alat bantu ukur load cell teknik mesin. J-Ensitec, 3(1), 9-13.Daryanto. (2012). Teknik Las. Bandung: AlfabetaGunawan, Y. Endriatno, N. Anggara, B, H. (2017). Analisa pengaruh pengelasan listrik terhadap sifat mekanik baja karbon rendah dan baja karbon tinggi. Enthalpy Jurnal Ilmiah Mahasiswa Teknik Mesin, 2(1), 2502-8944.Imam, P, M. dan Sarjito, J, S. (2012). Analisis kekuatan sambungan las smaw (shielded metal arc welding) pada marine plate st 42 akibat faktor cacat porositas dan incomplete penetration. KAPAL, 5(2), 102-113.Kolo, J.M., Nugraha, I.N.P. & Widayana, G. (2017). Pengaruh variasi arus terhadap kekuatan impact dan kekerasan material st 37 menggunakan proses pengelasn gas tungsten arc welding (GTAW). Jurnal Pendidikan Teknik Mesin Undiksha, 8(2), 1-10.Kurniawan, S, A., Solichin & Puspitasari, P. (2014). Analisis kekuatan tarik dan struktur mikro pada baja st.41 akibat perbedaan ayunan elektroda pengelasan SMAW. Jurnal Teknik Mesin, 22(2), 1-12.Mohruni, A, S. dan Kembaren, B, H. (2013). Pengaruh variasi kecepatan dan kua arus terhadap kekerasan, tegangan tarik, strukturmikro baja karbon rendah dengan elektroda e6013. Jurnal Rekayasa Mesin, 13(1), 1-8.Pranawan, D, F, B. dan Suwito, D. (2016). Pengaruh teknik pengelasan alur spiral, alur zig – zag, dan lurus pada arus 85 a terhadap kekuatan tarik baja st 41. Jurnal Teknik Mesin. 4(2), 29 – 32.Siswanto & Amri, S. (2011). Konsep dasar teknik las. Edisi 1. Jakarta : PT. Prestasi Pustakaraya.Weman, K. (2003). Welding processes handbook. Woodhead Publishing Limited, Cambride.Widharto, S. (1996). Petunjuk kerja las. Jakarta: Pradnya ParamitaWiryosumarto. 2000. Teknologi pengelasan logam. Jakarta: PT. Pradnya Paramita.

Design and Experiment Study of Ultrasonic Longitudinal-Torsional Compound Consolidation Vibration System for Metal Foil

In order to realize the connection for metal foil, a longitudinal-torsional compound consolidation vibration system is proposed, and relative experiments are carried out. Firstly, the structure of longitudinal-torsional compound consolidation vibration system was designed, detailed structural design of the compound piezoelectric transducer and the compound horn in the vibration system was carried out, and torsional vibration analysis of the compound horn with spiral grooves was carried out based on mechanical principle. Secondly, modal calculation and harmonic response analysis of longitudinal-torsional compound consolidation vibration system were carried out, and corresponding vibration mode and harmonic frequency were obtained. The effect of structural parameters for the compound horn on the frequency of the consolidation vibration system was analysed, and structural parameters of the compound horn were optimized. Finally, the prototype was made, and the experimental platform was built to test the amplitude. When the frequency is near 20000 Hz, the resonance is achieved in three directions at the same time, and the resonance frequency is 19800 Hz. Through the frequency-scanning test, the maximum longitudinal amplitude of the consolidation vibration system is 16 μm, and the maximum torsional amplitudes of X and Y are 7.9 μm and 8.1 μm. The longitudinal-torsional compound consolidation vibration system can realize the connection of the same and different metal foils and has broad application prospects.

Analysis of the Surface Roughness of a Tube Drawn by a Fixed Mandrel

The manufacture of tubes by a fixed mandrel drawing is one of the technologies in the manufacture of seamless tubes. This is the oldest tube drawing method. It uses a mandrel at the end of the die to shape the internal diameter of the tube. This process is slow and the area reductions are limited (lengths of tubes are limited), but it gives the best inner surface finish of any of the processes. The use of a fixed mandrel by the drawing of small-diameter tubes makes it possible to increase the accuracy of the inner surface and improve the quality. The paper presents the results of solving a partial task in this area. It deals with the reconstruction of the microgeometry of the inner surface of a tube drawn by a fixed mandrel. Tubes (STN 41 1353) were drawn through dies with different reduction angles. There were grounds the straight and spiral grooves on used fixed mandrels. On the inner surface of the tube were formed grooves after drawn that had a different surface roughness compared to the mandrel surface. The paper graphically presents the morphology of obtained surfaces under various conditions (reduction angles, straight/spiral grooves on the fixed mandrel) as well as measured surface roughness values. At the end of the paper, the knowledge gained through experimental research are summarized.

Finishing Performance of the Abrasive Flow Machining in Complex Holes by Using Helical Cores

Since abrasive gels with single direction motion are very difficulty to achieve the smooth surfaces in the complex holes finishing during abrasive flow machining (AFM), therefore, the helical cores were proposed here to create the multiple motions of abrasive gels to get the even surface of the complex holes in AFM. The results showed that helical core with 5 spiral grooves and narrow gap between the core tip and the hole could obtain the even surface and fine surface roughness after AMF.

Barrel heating with inductive coils in an injection molding machine

Traditional injection molding machines use resistance heating (RH) bands to heat the barrel. However, RH has a low energy rate; thus, the time required to reach the target temperature is rather long. Consequently, the use of inductive techniques, with a faster heating rate and improved energy rate, has attracted growing interest in recent years. However, an inappropriate design of the inductive coils and plasticization barrel may result in a strong repulsive magnetic field between neighboring coils and a corresponding reduction in the heating performance. Thus, developing an appropriate inductive heating design is essential in improving the barrel heating performance. The present study therefore performed a simulation and experimental investigation into the magnetic field and temperature distribution for different barrel geometries and coil current designs. The simulation results showed that the application of spiral grooves to the barrel improved both the heating rate and the temperature uniformity (TU) and effectively solved the proximity effect. The results indicated that the application of induction heating together with a novel grooved barrel design yields an effective improvement in both the thermal efficiency and the TU compared to that achieved using the traditional RH method with a single- or double-section barrel.

Analysis of static and dynamic characteristics of spiral-grooved gas journal bearings in high speed

The spiral grooves structures could promote load capacity and improve stability of the gas journal bearings working in high-speed condition. In this study, the unsteady Reynolds equation is solved by linear perturbation method and finite difference method in which the mesh of the groove region is specially treated. The static and dynamic characteristics of spiral grooves journal gas bearings are investigated in different working conditions and the pumping effect caused by spiral-groove structure is revealed and analyzed. Further, the influences of groove structural parameters on the dynamic stiffness and damping coefficients are studied and discussed, which provides guidelines for the design of the journal gas bearings with spiral grooves.