Applied Mechanics and Materials Vol. 775

Abstract: Contribution is aimed on lost heat of plate heat exchangers to surrounding environment. Heat losses to vicinity are insignificant relative to transferred heat flow in the plate heat exchangers. This small part of the lost heat is demonstrated in parametric case study of plate heat exchanger, where is the lost part of heat energy lower than 0.50 % in ordinary cases.

Abstract: This study investigates the application of PTFE wicks to flat-plate loop heat pipes (FLHPs). PTFE’s low heat transfer coefficient effectively prevents heat-leakage, which is a problem with using metal wicks, lowering the operating temperature and pressure. This paper uses PTFE particles to form wicks, and the effect of PTFE on flat-plate LHP performance is investigated. Experimental results shows that the highest heat load reached was 100W, with lowest thermal resistance of 0.61°C/W, and heat flux of about 10W/cm², For the wick properties, the wick had an effective pore radius of the wick was around 9.2μm, porosity of 47%, and permeability of 1.0 x 10^-12m². Compared to the highest heat flux reported in literature thus far for PTFE flat-plate LHPs, the heat flux in this study was enhanced by around 50%.

Abstract: The rapid engineering aero-heating calculation method for hypersonic vehicles is established for the question of computational efficiency during conceptual design stage. First the pressure distribution along vehicle’s surface is calculated by modified Newtonian theory. Secondly, the streamline along the surface is calculated with Newtonian steepest decent concept. Then by using reference enthalpy method, the heat flux on the surface is given. Finally, the heat flux on the surfaces of blunted cone, lifting body and wave-rider vehicle is calculated The analysis result shows the method used in this paper is fit for hypersonic vehicles, and can satisfies the aero-heating calculation during conceptual design stage in both efficiency and accuracy.

Abstract: In order to improve underwater blast shoveling reliability, a new device, namely the clamping device with locking function for underwater hydraulic impulsion shovel, was proposed in this paper. First of all, according to the principle of underwater hydraulic impulsion shovel, the existed structures and features of the clamping device are analyzed. Secondly, the clamping device with locking function is presented under used conditions. The design and calculation of the clamping device are presented. Finally, the clamping device model is established based on ergonomic design principles of the clamping device, which proves that the method is feasible and effective.

Abstract: A study of non-Newtonian inertia squeeze film in rectangular stepped plates has been presented in this paper. Applying the momentum integral method incorporating the micro-continuum theory of non-Newtonian fluids, a non-Newtonian inertia lubrication equation is derived. It is found that the fluid inertia effects yield in a higher normal load capacity as well as a longer squeeze film time as compared to the non-Newtonian stepped squeeze film in the absence of fluid inertia forces.

Abstract: The variation rate of seed-spaces in soil is higher and the qualification rate is lower due to the high seed releasing position of double discs furrow opener of no-tillage planter. To solve this problem, a new belt-type device for air-suction metering was designed and its main structural parameters was determined based on the cavitation time analysis of seed meter. This device integrated both transmission mechanism and seed releasing mechanism into one system, matching with the rotating speed of seed disc and the walking velocity speed of planter. The optimal parameters in relating to seeding performance were obtained by orthogonal test. When the seed releasing height is 100 mm, the rotational speed of seed disc is 30 r/min and the pressure of negative room is 3.5 kpa, the qualification rate of seed-space, the missing rate and multiple rate of seed per hill can be 98.5%, 0.48% and 1.02%, respectively.

Abstract: Solar-powered aircraft of wing-sail configuration employ sail tails mounted with photovoltaic (PV) modules, which could maximize solar energy absorption by rotation around individual roll axes or by yawing control of the aircraft. The guidelines of determining primary parameters for the wing-sail configuration differ significantly from solar-powered aircraft of conventional configuration. Effects of top-architecture mission requirements under the constraints of energy balance and mass balance are explored to investigate flight principles of the wing-sail configuration. The results show that the wing-sail has more potential for year-round operation at wide latitudes, equilibrium ceiling capacity of the wing-sail still differs significantly in a whole year: higher near summer and lower near winter and larger payload mass leads to higher payload-carrying capacity.

Abstract: This study examines thermal resistance under natural convection for two different types (Type A and Type B) of pin-fin heat sinks with/without a hollow in the heated base. The effects of the rate of heat transfer, the height of fin, the finning factor, the heat sink porosity and the perforated base plate on the thermal resistance were investigated and evaluated. Experimental results show that thermal resistance, using pin-fin heat sinks, is significantly different for Type A and Type B.

Abstract: This paper aims in particular to do a case study of the numerical efficiency of the application of LSFEM (Least Squares Finite Element Method) in the solution of heat conduction problems in multi-connected domains. To demonstrate this study two cases (the first with exact solution for comparison of results) are presented in the same multi-connected geometry, of easy construction, to facilitate the comparison of the results of this paper with future studies of other researchers.

Abstract: The wheelchair is one of the most used equipment for moving people with motion deficit in the lower limbs. The objective of this work was to design a KIT adaptable to a conventional wheelchair, turning it into an electric tricycle, in order to facilitate the movement of wheelchair users. This KIT enables the adaptive wheelchair travel greater distances in less time, making more quality of life. A structure was designed to fit in a conventional wheelchair, with the aid of CAD tools. This structure is sized to be able to withstand the stresses to which it is submitted. The adaptive KIT presented in this work can be used in a wide variety of models of wheelchairs and is functional, safe, and economically viable.