3D Model-Based Simulation Analysis of Energy Consumption in Hot Air Drying of Corn Kernels

To determine the mechanism of energy consumption in hot air drying, we simulate the interior heat and mass transfer processes that occur during the hot air drying for a single corn grain. The simulations are based on a 3D solid model. The 3D real body model is obtained by scanning the corn kernels with a high-precision medical CT machine. The CT images are then edited by MIMICS and ANSYS software to reconstruct the three-dimensional real body model of a corn kernel. The Fourier heat conduction equation, the Fick diffusion equation, the heat transfer coefficient, and the mass diffusion coefficient are chosen as the governing equations of the theoretical dry model. The calculation software, COMSOL Multiphysics, is used to complete the simulation calculation. The influence of air temperature and velocity on the heat and mass transfer processes is discussed. Results show that mass transfer dominates during the hot air drying of corn grains. Air temperature and velocity are chosen primarily in consideration of mass transfer effects. A low velocity leads to less energy consumption

Intermediate Model Design in the Progressive Stamping Process of a Truss Core Lightweight Panel

The truss core panel has been verified to be effective for structural weight reduction in former research studies. However, it is difficult to manufacture using the sheet metal pressing method because the forming height of the truss core panel is limited by the physical properties of the material. Although progressive stamping has been used to solve this problem, it is still difficult to practically use the truss core panel. In this study, the author proposed a manufacturing method and a hexagonal frustum intermediate structure to improve the forming quality of truss core panels using a progressive stamping method and verified its effectiveness through numerical analysis and prototype experiments. Compared to the conventional hemispherical intermediate model, the manufacturing process of the truss core panel using the proposed method was significantly improved

Intermediate Model Design in the Progressive Stamping Process of a Truss Core Lightweight Panel

The truss core panel has been verified to be effective for structural weight reduction in former research studies. However, it is difficult to manufacture using the sheet metal pressing method because the forming height of the truss core panel is limited by the physical properties of the material. Although progressive stamping has been used to solve this problem, it is still difficult to practically use the truss core panel. In this study, the author proposed a manufacturing method and a hexagonal frustum intermediate structure to improve the forming quality of truss core panels using a progressive stamping method and verified its effectiveness through numerical analysis and prototype experiments. Compared to the conventional hemispherical intermediate model, the manufacturing process of the truss core panel using the proposed method was significantly improved

Design and Manufacturing Process of a New Type of Deep-Sea Spherical Pressure Hull Structure

Spherical shell structures are the most suitable shape for deep-sea pressure hulls because they have ideal mechanical properties for handling symmetrical pressure. However, the shape accuracy requirement for a hull in a spherical shell structure subjected to deep-sea pressure is extremely high. Even minor asymmetry can significantly degrade its mechanical properties. In this study, a new type of spherical deep-sea pressure hull structure and its integral hydro-bulge-forming (IHBF) method are proposed. First, 32 flat metal plate parts are prepared and welded along their straight sides to form a regular polygonally shaped box. Next, water pressure is applied inside the preformed box to create a spherical pressure vessel. We performed a forming experiment using a spherical pressure vessel with a design radius of 250 mm as a verification research object. The radius of the spherical pressure vessel obtained from the forming experiment is 249.32 mm, the error from the design radius is 0.27%, and the roundness of the spherical surface is 2.36 mm. We performed a crushing analysis using uniform external pressure to confirm the crushing and buckling characteristics of the formed spherical pressure vessel. The results show that the work-hardening increased the crushing and buckling load of the spherical pressure vessel, above that of the conventional spherical shell structure. Additionally, it is established that local defects and the size of the weld line significantly and slightly affected the crushing and buckling load of the spherical pressure hull, respectively

The Development of an Assembled Truss Core Lightweight Panel and Its Method of Manufacture

In this study, a new assembled truss core panel and the method for processing it were proposed in order to improve the performance of the lightweight panel structure. The proposed assembled truss core panel can be easily processed by simple punching and bending. A processing experiment on an assembled truss core panel was conducted using an aluminum plate with a thickness of 1.0 mm, and the validity and performance of the proposed processing method were verified. A three-point bending test was performed using an assembled truss core panel obtained using the processing experiment. The assembled truss core panel had a relatively high bending stiffness in its early elastic deformation and a relatively long-lasting bending deformation after the initial failure. Its application as a lightweight panel has been confirmed. In order to compare it with the most commonly used honeycomb lightweight panel, FEM (finite element method) analysis was performed on the assembled truss core panel and on the honeycomb panel under the same conditions. The bending stiffness of the assembled truss core panel was found to be 10.60% higher than that of the honeycomb panel. Furthermore, to improve the productivity of the assembly-type truss core panel, construction of a production line using progressive dies was proposed, and the possibility of practical development for mass production was examined

Projection of global wind and solar resources over land in the 21st century

This study modelled projected spatiotemporal changes in global wind and solar resources over land in the 21st century under the RCP2.6 and RCP8.5 climate scenarios using an ensemble mean drawn from 11 Coupled Model Inter-comparison Project Phase 5 (CMIP5) models. These models’ performances were verified by comparing historical global near-surface wind speed and downward surface solar radiation over land. Compared to the baseline historical period 1985–2005, the distribution of relative projected changes in global wind and solar resources had great spatial and seasonal discrepancies. Under both climate scenarios, projected wind resources throughout the 21st century presented a decreasing trend in Asia and Europe but an increasing trend in the low-latitude Americas. In comparison, projected global solar resources over land generally showed an increasing trend throughout the 21st century, especially in Europe, eastern Asia, and eastern North America. Moreover, wind resources in the Americas had their most significant decrease and increase in January and July, respectively, while in Asia and Europe the decreasing trend as most prominent in January and October, respectively. The most significant increases in solar resources in the Americas, Asia, and Europe happened in October and July, respectively. Discrepancies between the variation trends of future global wind and solar resources suggest the complexity and nonlinearity of these resources’ responses to future climate change. Keywords: Wind and solar resources, Future projection, Climate change scenario, CMIP projec