Vacuum Infusion Simulation for Radome Manufacturing Using Woven Flax Fibre and Glass Fibre

The vacuum infusion method is emerging to produce composite parts, especially thin wall structure aircraft radome. Ansys Fluent is used in the optimization phase for mould filling analysis on aircraft radome part. The permeability fibre is referring to the physical property of the fibre reinforcement to allow fluids to permeate it, thus it is correlated with the viscosity of the resin used. In this work, flax fibre, glass fibre and low viscosity epoxy resin are used to determine the permeability value of flax fibre, glass fibre and hybrid without using a flow medium. In-plane experiment on reinforcement fibre permeability is conducted and all reinforcement fibre have similar fibre architecture and weight. The development of a digital model from a top partial aircraft radome is obtained through a 3D scanner and CATIA. Ansys Fluent is used to optimize the location of the injection line and air vent for the epoxy. The Ansys Fluent analysis model is validated through the in-plane experiment filling time result for a flat model. Based on the simulation analysis, the location of the injection line is placed at the perimeter and the air vent at the centre. The filling time from the simulation for the flax fibre and hybrid fibre was estimated around 10 to 11 minutes. However, the filling time for glass fibre is approximate 2 hours which is longer than epoxy gel time. Furthermore, this method can be used in mould filing scenarios of thin wall structure within gel time of the resin.

Influence of cross-section geometry on air demand ratio in high-head conduits with radial gate

When the gate of a high-head conduit is partly opened, a negative pressure draws the air in through the air vent. Air that is entrained into the water is instantly forced downstream in the form of air bubbles. When the studies on high-head gated conduits were examined, it was determined that the air demand ratio varied depending on many hydraulic and geometric parameters. This work focused on determining the effect of conduit cross-section geometry on the air-demand ratio. A series of experiments were carried out on high-head radial gated conduits having different cross-section geometries. Experimental results showed that conduit cross-section geometry was an important effect on the air demand ratio especially in small gate opening rates. Further, design equations for the air demand ratio were presented relating the air demand ratio to Froude number, gate opening rate, and ratio of gate opening to conduit length.

Application of compact silencers as a noise barrier to a naturally ventilated double-skin façade

A prior study of the acoustical performance of a double-skin facade (DSF) as a noise barrier was carried out based on the percentage of the air vent open surface area, shading louver configurations, and shading louver surface materials. Earlier research findings led to experimental investigations of the acoustical performance capabilities of compact silencers to replace DSF air vents as both noise barriers and air channels because DSF air cavities, which contribute to natural ventilation performance (e.g., wind-driven or buoyancy-driven performance), are acoustically vulnerable to noise transmitted through the air vents. This experimental investigation aims to explore noise reduction (NR) through compact silencers applied to DSF air vents. Double-skin facade mock-up test cases were designed based on three test scenarios of a ventilation open surface area: (1) a 100%air vent open surface area (open mode), (2) a 0% air vent open surface area (closed mode), and (3) a compact silencer. From a data analysis of DSF mock-up test results, the overall NR values of a DSFmock-up ranged from20 to 37 dB(A) depending on the number of compact silencers and the shading louver orientation used. Configurations of compact silencers and shading louvers helped the DSF mock-up achieve additionalNR values of 5 to 10 dB(A) depending on the test case. Moreover, applying compact silencers to a naturally ventilated DSF mock-up led to significant noise reduction at low frequencies (125Hz).

Performance improvement of an industrial control enclosure cooling system

Following the trend of high-accuracy machining, thermal management of industrial control enclosures become a critical issue. Therefore, a well-designed enclosure cooling system is essential to manage the heat generation inside the enclosure. In this study, to improve the performance of cooling system and the air flow distribution inside the enclosure, computational fluid dynamics (CFD) simulation has been used to evaluate the application of using the auxiliary circulation fan and air baffler. Furthermore, this study also investigates the layout design for both supply air vent and return air vent arrangement by two types of commercialized cooling systems through field measurements. The simulation results show the short circulation of airflow is improved when the air baffler is installed. It also shows that the auxiliary circulation fan is suggested. Besides, air baffler is used to enhance the temperature distribution. The experimental results reveal the upper supply vent arrangement will cause the short circulation of airflow slightly. And, the auxiliary circulation fans can improve the heat dissipation of cooling systems. There is no short circulation of airflow for the lower supply vent arrangement, but the supply air cannot be distributed smoothly by the auxiliary circulation fans because the shape of the air baffler is not properly designed.

Study on volcanic reservoir characteristics of Yingcheng Formation in Xudong area of Xujiaweizi fault depression

Types of deep reservoir rich in Yingcheng formation of Xudong area in Xujiaweizi fault depression, the study of volcanic rocks of Yingcheng formation in the main, using the date of core, logging, oil test, from lithology, lithofacies and physical properties to study volcanic reservoir characteristics. The main lithology of volcanic reservoir in Yingcheng formation of Xudong area include rhyolite, rhyolitic tuff, rhyolitic tuff fused, rhyolitic breccia and rhyolitic tuff breccia. In accordance with lithology combination of features, volcanic facies can be divided into volcanic explosive facies, volcanic effusive facies and volcanic sedimentary facies. The main types of porosity have air vent of primary pore, remnants pores of air vent filled after, cracks, micro-cracks and feldspar corrosion hole of secondary porosity, volcanic ash corrosion hole, micro-pore produced by rhyolitic glass from glass off in spherules rhyolite, quartz crystal chip corrosion hole, and so on. Through studying the ratio of reservoir and formation for a single well, the frequency distribution of reservoir thickness, production capacity situation and pool-forming regularity, Xudong area can be divided into three reservoir development zone, so we will find out the most favorable reservoir development zone, then it can play a guiding role for the next step of the exploration deployment.

Study on the Thermal Environment Inside a Fully-Enclosed Subway Noise Barrier

The thermal environment inside a fully-enclosed subway noise barrier shall be designed according to underground section tunnel standards. This article constructs a model using practical examples, simulates calculations on fully-enclosed noise barrier installations both with and without air vents via a threedimensional numerical simulation method, and then conducts a comparative analysis of the effects noise barrier lengths and air vent widths have on an internal thermal environment. The calculation results show that when the length of the fully-enclosed noise barrier without air vents was 100m, the internal thermal environment exceeded the limit; as the width of the air vents increased, the temperature in the internal environment gradually decreased, but the reduction was less once the air vent width exceeded 2 m; When the top air vent width was 2 m, and the noise barrier length was 100m, the thermal environment was found to meet requirements. As the noise barrier length increased, the internal air temperature exceeded the standards by varying degrees.