The load that borne by ship mining system is very complex. The vibration of lifting pipe can be significantly affected by ocean current and wind load, which has a key impact on material lifting, ore bin storage and ship towing. Considering the composite load condition, the vibration control equation of mining ship is established based on the transverse swing mechanism of ship hull, and the variation law of transverse disturbance is obtained. The dynamic equation is constructed according to the bearing characteristics of the lifting system and the D'Alembert principle. The Wilson method is used to analyze and obtain the transverse vibration spectrum response of the lifting pipe under different wind loads, hull disturbance velocity and water depth. Based on the analogy method and hammering method, the vibration feedback test-bed of the lifting system is built, and the time-domain and frequency-domain vibration characteristics of the lifting pipe model under different water depths are obtained. The results show that in shallow water, the disturbance of mining ship and the composite load of ocean current are the key factors affecting the vibration amplitude of lifting pipe respectively. With the increase of water depth, the characteristic frequency and amplitude of the system decrease, and the amplitude gradually presents a discontinuous phenomenon.

聚光太阳能发电技术提供了一种可再生能源转换系统,其中接收器是聚光太阳能发电系统的关键部分.文中利用DDPM-DEM模型对双腔式流化床接收器内的稠密颗粒流动和传热过程进行数值模拟,模型中考虑了颗粒的流动、碰撞和传热作用.基于欧拉-拉格朗日方法对太阳能流化床颗粒接收器中的气固两相流动进行建模,辐射源相和接收器内辐射场的相互作用通过DO模型描述.得出稠密颗粒内循环流动可以增强接收器内颗粒与气体之间的热传递效果,同时接收器内的温度分布也更加的均匀,颗粒温度和气体温度都得到很大提高,分别达到1400 K和1200 K.

In this paper, numerical simulation is carried out for the beam-type fluidized bed receiver. The mixture of air and inert particles is used as heat transfer medium in the simulation. Eulerian-Lagrange method and DO radiation model are used to describe the flow and heat transfer characteristics of gas and inert particles in fluidized bed receiver. At the same time, DPM method is used to consider the effect of particles on radiation field and the inter-action between particles and flow field. Tracking particle wrapping and the temperature distribution, flow and heat transfer process of particles are analyzed. The particle temper-ature distribution is mainly concentrated in 550-800 K, and 70% of the particles participate in effective heat transfer in terms of radial particle temperature and volume distribution. When the number of high temperature particles reaches 50%, the heat absorption capacity of mixed medium is optimal. At the same time, the fitting function with particle volume fraction as independent variable is obtained. (c) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

As a new type of combustion device, circulating fluidized bed has overcame many disadvantages of coal fired industrial boilers. It has improved combustion efficiency and reduced pollutants.The heat transfer characteristics related to fluidized bed are expensive and are subject to environmental conditions.The FLUENT17.0 software is used as a platform for numerical simulation to solve.Numerical simulations are based on experiments by Tong Zhao et al. A simplified two-dimensional structure of circulating fluidized bed is applied to simulate the internal flow process and combustion process, and the heat transfer problem of fluidized bed is further studied. Based on the heat transfer model, the influence of the bed temperature and radiation heat transfer on the total heat transfer coefficient is researched.After theoretical calculation, the three distribution laws of heat flux density along the height direction of reactor are found, which provides reference for optimization reference.

Based on the Kinetic Theory of Granular Flow (KTGF), the second-order moment (SOM) model is developed for particles phases considering the anisotropy of fluctuating velocity in biomass gasification process. Coupled with chemical kinetics method, the chemical reactions of biomass gasification are described and the fluctuating anisotropy of particles is analyzed in bubbling fluidized bed (BFB). The simulated molar fractions of gas species are in good agreement with experimental data, and the comparisons with KTGF model and SOM model are simulated. The instantaneous fluidization process in BFB is analyzed, and the SOM and fluctuating anisotropy for biomass gasification is investigated. The mean value of second-order moment is higher while the fluctuating anisotropy is lower for the particles with lager diameter in computational domain. (C) 2018 Published by Elsevier Ltd.