Influence Of Flow Behavior Research Articles

Effect of behavior of oil–air lubrication flow on characteristic of point contact sliding wear

PurposeThis paper aims to investigate the influence of oil–air lubrication flow behavior on point contact sliding wear characteristics.Design/methodology/approachOil–air lubrication equations between point contact counterparts were established on the basis of volume of fluid model. The effects of oil supply and injection azimuth on oil-phase volume fraction and its pressure distribution were simulated with commercial software Fluent. Characteristics of point contact sliding wear were then tested with an MFT-3000 friction tester under oil–air lubrication condition. The influence of flow behavior on wear characteristic was investigated combined with numerical and experimental results. The wear mechanism was revealed using SEM, EDS and ferrography.FindingsWhen air supply speed is constant, the oil-phase volume fraction increases with the increase in oil supply, which helps form continuous oil film and decrease the sliding wear evidently. The injection angle and distance considerably influence the oil–air flow behavior. When injecting at a certain distance and angle, the oil-phase volume fraction reaches its maximum, and the abrasion loss is minimal. Under the test conditions in this study, abrasive particles are mainly debris and a few spiral cuttings. The wear mechanism is abrasive wear.Originality/valueThe influence of the behavior of oil–air lubrication flow on the characteristic of point contact sliding wear is analyzed. This work provides guidance for the application of oil–air lubrication technology in point contact friction pairs.

Response to the comments made by Khalid M. Saqr on our paper titled “CFD analysis on the influence of helical carving in a vortex flow solar reactor”, Int. J. Hydrogen Energ. 2010: 35, 6248–6260.

In our paper titled “CFD analysis on the influence of helical carving in a vortex flow solar reactor”, we have presented a 3D CFD analysis of a turbulent and reactive flow for directly irradiated solar thermochemical reactor to characterize the influence of flow behavior on the heat transfer and solar cracking process. The heat transfer by radiation from carbon particles is considered by providing global absorption and scattering coefficients in the computational domain obtained from Mie code. The flow field is based on RNG k-3 model derived using renormalization group theory. We have validated our numerical procedure by comparing the outlet temperature and cavity temperaturemeasurements of Hirsch and Steinfeld (Solar hydrogen production by thermal decomposition of natural gas using a vortex-flow reactor. Int J Hydrogen Energy 2004; 29:47-55) for Run 1 Configuration 1. As it is seen in our paper, our numerical simulations predict the mixture (gas-particle) flowoutlet and cavitywall temperatures as 1240K and 1751.3K,which deviates from the experimentally