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This paper reports on the findings of first of its kind to examine motorbike’s chain transmission, focusing on chain lubrication and its effect on the temperature, efficiency and vibrations of the transmission. The novelty of the paper is to investigate holistically the lubrication effect on the transmission by comparing its dynamic performances under three different lubrication conditions: chain not lubricated at all, chain lubricated with a spray polytetrafluoroethylene (PTFE) addicted lube and chain lubricated with a mineral oil at every minute of the test.

A novel mechatronic test rig has been designed and manufactured using a thermocamera, a dynamometer and an accelerometer respectively. The rig enables a multi-parameter dynamic and real-time sensing investigation of any motorbike chain system by recording temperature, transmission's efficiency and vibrations for any tests by. An experimental investigation has been conducted by running a chain under three aforementioned lube conditions at different speeds with the purposes of: (A) measuring the effect that each lube condition has on three critical parameters: temperature, vibrations and the efficiency of the transmission, and (B) identify the best conditions for practical use.

Results showed that proper use of lubricant can increase the efficiency of the system, by an estimated average of 4.1% is desirable. Additionally, using a continuous lubrication with a mineral oil lubricant leads to better transmission compared to the use of the spray PTFE from the efficiency and thermal points of view.

This work presents an experimental investigation on the effect of two different kinds of lubrication form motorbike chain on transmission’s efficiency. The findings are still valid for different applications of chain transmission in dirty environments. Novelty of the paper is highlighted as follows: this is the first work scientifically investigating the importance of lubrication on chain in harsh environments, particularly of motorbike chain. The work reports a comprehensive lete set experiments and analysis of thermal and mechanical effect because of the presence of lubricant has never been shown. Three kinds of lubricants have been used, and show their distinctive effects which are separately highlighted.

This study aims to present a new haptic-enabled virtual assembly system for the automatic generation and objective assessment of assembly plans. The system is intended to be used as an assembly planning tool along the product development process.

The generation of product assembly plans is based on the analysis of the assembly movements and operations performed by the user during the virtual assembly execution, and the objective assessment of product assembly is based on the definition and computation of new proposed assembly metrics.

To evaluate the system, a case study corresponding to the assembly of a mechanical component is presented and analyzed. The results demonstrate that the proposed system is an effective tool to plan and evaluate different product assembly strategies in a more practical and objective approach than existing assembly planning methods.

Although the virtual assembly execution time is larger than the real assembly execution time, the assembly planning and evaluation results provided by the system are valid. However, the development of higher performance collision detection algorithms is needed to reduce the simulation time.

The proposed virtual assembly system is able to not only simulate and automatically generate assembly plans but also objectively assess them from the virtual assembly task execution. The introduction and use of several assembly performance metrics to objectively evaluate assembly strategies in virtual assembly also represents a novel contribution.

The serious friction and wear problem occurs on the mechanical seal’s faces during the start-up stage of the high-speed turbopump for a liquid rocket engine. This paper aims to propose a kind of thick metal alloy coatings on the surface of the seal’s rotor so as reduce the friction and wear.

With the pin-disk (the graphite pin and the disk with the metal coating) tribology-tester, the tribological behaviors of four metal coatings are investigated. The special friction coefficients under the dry friction, boundary friction and different temperatures of water-lubricated conditions were obtained.

The test results show that the thick metal coating has a good performance of the wear resistance and friction reduction; and the friction coefficients of a Sn-Sb-Cu coating under the dry friction and water-lubricated conditions are 0.377 and 0.043, respectively, and the corresponding mass wear volumes are only 2.74 and 0.81 mg, respectively.

The thick metal coating scheme for the mechanical seal’s faces might lend itself to the harsh working conditions of the low-viscosity liquid rocket engine.

A hybrid bearing of advanced cryogenic rocket engine turbopump is designed. For cryogenic fluid propellants (such as liquid oxygen) as the lubrication of bearing, bearings operating close to liquid-vapor region (near the critical point or slightly sub-cooled) are likely to develop a two phase flow region. The paper aims to discuss these issues.

In this paper, an all liquid, liquid-vapor mixture, and all vapor, i.e. a continuous vaporization bulk flow model of density and viscosity for mixture fluid, is presented, and the general Reynolds equation and energy equation with two phase flow as lubricants is solved. The static and dynamic performance of a 50-mm-radius hybrid bearing are obtained under 20,000 rpm speed and 10 MPa supply pressure.

The results show that the variations of performance of bearing operating under cryogenic liquid oxygen are not bounded by the all liquid and all vapor cases in the liquid-vapor mixture range. There behaviours are attributed to the large change in the compressibility character of the flow.

For validating the correctness of analytical model, an experimental study on the liquid-vapor nitrogen mixture lubricated hybrid journal bearings is being carried out where low-viscosity nitrogen was selected as the lubricant for the sake of safety. Soon after, the authors will discuss the results and publish them in the new papers.

An all liquid, liquid-vapor mixture, and all vapor, i.e. a continuous vaporization bulk flow model of density and viscosity for mixture fluid, is presented. The static and dynamic performance of hybrid bearings with two phase flow as lubricants are obtained.

A new type of hydrostatic and hydrodynamic non-contacting face seals has been designed to meet the requirements of lower leakage, longer life and more repeatedly start and stop on shaft seals raised by liquid rocket engine turbopumps. And an experimental study on the performance of the face seal in the actual liquid oxygen turbopump was completed where low-viscosity water was selected as the seal fluid for the sake of safety. The paper aims to discuss these issues.

Different performances of face seals under preset conditions were obtained by repeatedly running tests, and the main performance parameters encompass leakage, fluid film pressure between the faces, operating power, face temperature, and so on.

The results indicate that the designed face seal has a smaller amount of leakage, with a minimum value of 3 ml/s. Furthermore, the designed face seal has been proved to demand lower operating power. Since its operating power changes slightly with different sealed fluid pressures, the new seal can be deployed in the harsh working condition with high pressure or with high speed (greater than 20,000 rpm). However, one proviso is that when liquid is employed as the seal fluid, the groove depth should be relatively deeper (greater than 10 μm).

In response to future engineering requirements, study on the controllable spiral-groove face seals to improve the current design is being conducted.

The advancement of such non-contacting face seals proffers important insights to the design of turbo-pump shaft seal in a new generation of liquid rocket engine with regard to the requirement of frequent start and stop as well as long life on it.