Field experimental study on the cooling effect of mine cooling system acquiring cold source from return air

With the increase of mining depth, more and deeper coal mines are limited by heat disaster. The cooling energy in deep mine cooling system comes from mine water inrush or ground cooling tower, but we cannot adopt the two methods because mine water inrush in many old coal mines in China is limited. What is more, the cooling pipelines cannot be put in narrow pit-shaft. To settle the problem above, according to the characteristics of Zhangxiaolou Coal Mine, this paper adopts the deep mine return air as the cooling energy for deep mine cooling system. In addition, we carried out cite test to extract cold energy from return air. Through monitoring the water quantity, water temperature of cooling system and air temperature, we got the thermodynamic equilibrium parameters during the cooling energy acquisition analysis and the effect of cooling system that the temperature and humidity on working face are respectively reduced to 8-12 ℃ and 8-15% through cooling. This research offers experimental reference for deep mine cooling which lacks cooling energy.

Tuning the velocity and flux of a low-velocity intense source of cold atomic beam

We investigate experimentally and numerically the quantitative dependence of characteristics of a low-velocity intensity source（LVIS） of atomic beam on light parameters, especially the polarization of cooling laser along the atomic beam axis（pushing beam）. By changing the polarization of the pushing beam, the longitudinal mean velocity of a rubidium atomic beam can be tuned continuously from 10 to 20 m/s and the flux can range from 3 × 10^-8 to 1 × 10^-9 atoms/s, corresponding to the maximum sensitivity of the velocity with respect to the polarization angle of 20（m/s）/rad and the mean sensitivity of flux of 1.2 × 10^-9（atoms/s）/rad. The mechanism is explained with a Monte-Carlo based numerical simulation method, which shows a qualitative agreement with the experimental result. This is also a demonstration of a method enabling the fast and continuous modulation of a low-velocity intense source of cold atomic beam on the velocity or flux,which can be used in many fields, like the development of a cold atomic beam interferometer and atom lithography.

Review on effect of applied internal cooling source and vibration on metal solidification process

Advancements in metallurgical technology have led to the emergence of high-performance requirements for metal materials,like high uniformity,high purity,and superfine crystallinity.This has resulted in the development and application of internal cooling source(ICS),vibrational,and vibrational internal cooling source methods in metal solidification processes to afford products with refined crystal grains and large proportions of equiaxed crystals.These methods have gradually been introduced into laboratories and some steel mills over the past few decades.However,there are few successful industrial applications of these methods,as there is no comprehensive understanding of their control theories and principles.Accordingly,the development,basic principles,and classifications of the three types of methods are summarized,and their impact on the solidification of molten metals and the morphology of solid products is discussed.In addition,experimental and numerical simulation-based researches on each type of method are reviewed and their prospects for applications are briefly discussed to control metal solidification.Finally,detailed future perspectives are provided on vibratory strip feeding,ICS,and pulsed magneto-oscillation methods.Hopefully,it will serve as a reference for future studies of the application of these and related methods in metal solidification processes.

Simulation study of a dual-cavity window with gravity-driven cooling mechanism

Utilization of high temperature cooling sources or natural energy sources can potentially contribute to improving energy efficiency in buildings.In this study,a dual-cavity window with gravity-driven cooling mechanism(GDC window)was proposed to integrate the low-grade cooling sources into the glazing system for improving the thermal performance of the window.The embedded pipes circulated with low-grade cooling water are the key component of GDC window,which can remove the absorbed solar heat and reduce the heat gain through the window.A numerical model based on CFD simulation was developed to analyze the flow characteristic and heat transfer within the GDC window.Model validation was conducted by comparing the simulation results with measurement data obtained from previous study.Numerical simulations were carried out to compare the thermal performance of GDC window with that of conventional blinds window.Sensitivity analysis was performed to evaluate the influence of some design parameters on the flow characteristic and thermal performance of GDC window.The simulated results show that compared with the blinds window,the GDC window reduces 57.4%and 40.4% of heat gain in summer for the low-grade cooling water of 18℃ and 25℃;respectively.Reducing the flow resistance within the GDC window is significant for improving the heat removal performance of the embedded pipes.This study provides an alternative solution to integrate the low-grade cooling sources into the glazing system for enhancing the energy-efficiency and decreasing the building energy demand in cooling-dominated buildings.