The effects of orientation of an inclined enclosure on laminar natural convection

Natural convective laminar flow is numerically investigated in a two-dimensional and square enclosure at various angles of inclination respect to horizontal. Two adjacent walls of the enclosure are insulated and the other two are kept at different temperatures. The influence of Rayleigh number representing the effects due to the differential heating of the enclosure walls as well as the effect of inclination angle on natural convection flow are studied. The flow field and isothermal lines show different patterns at high Rayleigh numbers. The average Nusselt number, maximum stream function and average temperature appear to be a little affected by the inclination angle at low Rayleigh numbers. However, as the Rayleigh numbers rises, these parameters behave differently at various inclination angles. In this study, the effects of inclination on the temperature along the centerline of the enclosure and the local Nusselt number along the cold wall are also examined. The results show negligible effects of inclination angle at low Rayleigh numbers and considerable effects at high Rayleigh numbers

Improving the performance of the hardy cross algorithm for large ventilation models

The Hardy Cross algorithm offers a reliable method of solving network systems of fluid flow and has become widely used for solving water and ventilation flow networks. A limitation is that computational iterations and time to solve a network rises rapidly with the size of the model and modern detailed ventilation networks have typically grown to thousands of airways. Non-linear matrix solving methods can offer improved performance, however these are more complex and may be unstable if initial estimates are poor. This paper presents improvements that can be applied to the traditional Hardy Cross algorithm to greatly reduce iterations and solving time for large ventilation models

Recent developments in fibre optic shape sensing

This paper presents a comprehensive critical review of technologies used in the development of fibre optic shape sensors (FOSSs). Their operation is based on multi-dimensional bend measurements using a series of fibre optic sensors. Optical fibre sensors have experienced tremendous growth from simple bend sensors in 1980s to full three-dimensional FOSSs using multicore fibres in recent years. Following a short review of conventional contact-based shape sensor technologies, the evolution trend and sensing principles of FOSSs are presented. This paper identifies the major optical fibre technologies used for shape sensing and provides an account of the challenges and emerging applications of FOSSs in various industries such as medical robotics, industrial robotics, aerospace and mining industry

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy

The effects of sample position and gas flow pattern on the sintering of a 7xxx aluminum alloy Al-7Zn-2.5Mg-1Cu in flowing nitrogen have been investigated both experimentally and numerically. The near-surface pore distribution and sintered density of the samples show a strong dependency on the sample separation distance over the range from 2 mm to 40 mm. The open porosity in each sample increases with increasing separation distance while the closed porosity remains essentially unchanged. A two-dimensional computational fluid dynamics (CFD) model has been developed to analyze the gas flow behavior near the sample surfaces during isothermal sintering. The streamlines, velocity profile, and volume flow rate in the cavity between each two samples are presented as a function of the sample separation distance at a fixed nitrogen flow rate of 6 L/min. The CFD modeling results provide essential details for understanding the near-surface pore distribution and density of the sintered samples. It is proposed that the different gas flow patterns near the sample surfaces result in variations of the oxygen content from the incoming nitrogen flow in the local sintering atmosphere, which affects the self-gettering process of the aluminum compacts during sintering. This leads to the development of different near-surface pore distributions and sintered densities

Hydromagnetic natural cooling of a triangular heat source in a triangular cavity with water-CuO nanofluid

This paper presents a numerical analysis of natural cooling of a right triangular heat source by a water-CuO nanofluid in a right triangular cavity that is under the influence of a horizontal magnetic field. A computational domain is defined and a numerical scheme based on the control volume formulation using the SIMPLE algorithm is developed. The convection-diffusion terms are discretised using a power-law scheme. The effects of the Rayleigh number, the solid volume fraction, the Hartmann number and the heat source position in the cavity on the heat transfer performance of the cavity are examined. The thermal performance of the cavity is enhanced as the Rayleigh number increases, the Hartmann number decreases and the distance of the heat source with the cold walls decreases. An optimum solid volume fraction is found that maximises the heat transfer at high Rayleigh numbers