冷却塔设计布置实例谈

冷却塔的噪声和水雾对周围的环境影响很大,尤其是大型建筑的冷却塔群,由于放置空间所限,在设计中对其进行合理的布置更显重要。通过工程实例,介绍了冷却塔有效排布的思路和方法。     

亚运自行车馆气流组织CFD的分析和探讨

介绍亚运自行车馆的空调方案,高大空间-观众区和赛场的气流组织,在观众区顶侧部和赛场的顶部设了送风,在前四排座位底和最后一排座位平台侧面进行回风,排风设在场馆最顶部,使用了CFD软件对观众区和赛场进行了三维数值模拟,通过分析模拟的结果表明:观众区和赛场气流组织是满足设计要求的,温度、速度、PMV、PPD、空气龄均较为合适...     

On the effect of turbulent intensity towards the accuracy of the zero-equation turbulence model for indoor airflow application

The zero-equation turbulence model for indoor airflow applications proposed by Chen and Xu [4] has obtained immense popularity amongst the CFD practitioners in HVAC industry. A uniform turbulent intensity of 10% has been assumed in their model. In this paper, following the analogy of Chen and Xu [4] in deriving the coefficient of their zero-equation turbulence model (0.03874) which is indeed expressed as a function of turbulent intensity, the effect of turbulent intensity value assumed in the model towards the solution accuracy is investigated in this paper. Three indoor airflow cases, i.e. forced convection, natural convection and mixed convection problems are studied. It has been discovered that as the assumed uniform turbulent intensity T_i is reduced, the solution accuracy is significantly improved and the prediction comes closer to those of the two-equation standard k-? model, LES model as well as the experimental data.     

地应力异常区域蠕变围岩上山支护技术研究

针对潞安常村煤矿S6 1号回风上山处于地应力异常区域及围岩具有蠕变性等特点进行分析,提出对初始支护段进行套棚加固,新掘段采用全长预应力锚固强力锚杆锚索组合支护系统进行支护,并进行了现场应用及矿压监测。监测表明,巷帮变形量较小,锚杆锚索受力稳定,说明支护有效控制了围岩变形,支护效果非常明显。     

流化床式气流粉碎机在煤超细粉碎过程中的应用

煤的超细粉碎是现代煤化工原料加工中主要的深加工技术之一。在分析煤基本特点的基础上,将流化床式气流粉碎机应用于煤超细粉碎。设计了一种用于煤超细粉碎的流化床式气流粉碎机。对该粉碎机的螺旋加料器和喷嘴进行了重点设计和计算,为煤超细粉碎及纳微米煤粉的制备提供了一种新方法。     

An investigation into the use of a wind shield to reduce the convective heat flux to a nocturnal radiative cooling surface

The effect of a wind shield on the convective heat flux from an ambient air stream blowing over a horizontal surface intended for nocturnal radiative cooling has been studied by computational fluid dynamical calculations and by wind tunnel experiments under conditions appropriate for the climate of Thailand. The test unit was a rectangular plate 312 mm×250 mm, with vertical metal strips for the wind shield having heights up to 100 mm along the edges of the plate. It was found that a wind shield of height 25 mm slightly increased the convective heat transfer due to increased turbulence over the surface, but wind shields of height 50 mm and 100 mm reduced the convection due to a separation of the main airflow from the surface. Radiative cooling was reduced by the wind shields. The net cooling of the surface was best with no wind shield at wind velocities less than about 1 m s^–1, and with the wind shield of height 100 mm at wind velocities greater than about 2 m s^–1.     

拉伐尔喷管射流中喷口激波处理的特征线法

用特征线方法对锥型喷管超音速流中形成的激波进行了计算，给出了两族特征线在激波后的存在区域和激波的特征线数值求解方法。一些计算结果妥析方法得到的结果进行了比较。对激波的特征线数值计算方法做了一些分析，并用它来处理超音速流中的激波。     

Experimental Investigation of Local Heat Transfer and Skin Friction in Tube Coils

Local heat transfer and skin friction around the tube perimeter of coils were studied in airflow. The heat transfer experiments were performed with two different coils D/d = 23 and 15.6, and skin friction experiments were performed with three different coils D/d = 25, 13.3 and 6.67 In the wide range of Re number from 4×103 till 105 . Variation of the local heat transfer around the perimeter and along the tube was defined. The behavior of the shear stresses at the wall and of the flow modes were studied. Investigations of the heat transfer indicated that with the increase of D/d the difference between heat transfer in the initial thermal section and the stabilized heat transfer increases. Investigations of the shear stress and its fluctuations indicated that, in large-curvature coils, the transition from laminar-vortex flow to turbulent flow around the tube perimeter takes place at different values of Re. In the region of the external generatrix of the bend, the transition occurs at smaller Re, whereas a     

A Study on the Estimation of Aeroheating upon the Warhead Nose at Supersonic Speed

An expression for estimating the aeroheating on a warhead nose at different supersonic speeds is proposed by incorporating CFD （computational fluid dynamics） and the least-square method. Compared with the traditional estimation formula, the expression is more accurate, convenient and can be used in the optimized design of warheads. The error from the result obtained in the test of a ball cartridge flight is less than 3 %. It satisfies the engineering requirements.     

肉鸡深加工车间低温空调设计

通过具体工程的设计和测试来详尽说明如何在肉鸡深加工车间实现低温空调以及在低温空调工况下的操作工人建立一个比较舒适的工作环境.经过二年多的运行实测证明,各项设计参数均达到要求.