Analysis of multi-layered filament-wound composite pipes under combined internal pressure and thermomechanical loading with thermal variations

The composite pipes manufactured by filament winding technology have anisotropic behavior owing to different reinforced ply angles. Composite pipes can be exposed to the thermomechanical loading due to hot fluid that flows into them. In this paper, based on the three-dimensional anisotropic elasticity, an exact elastic solution for thermal stresses and deformations of the pipes under internal pressure and a temperature gradient has been studied. Giving heat convection conditions the variation of temperature field within the pipe is obtained by solving the conduction equation at the wall. The influence of temperature field in the governing equations of thermoelasticity has been considered via a constitutive law. The shear extension coupling is also considered because of lay-up angles. Stress, strain and deformation distributions for different angle-ply pipe designs are investigated using the present theory.     

Cooling load reduction of building by seasonal nocturnal cooling water from thermosyphon heat pipe radiator

In this study, a concept of using thermosyphon heat pipe to extract heat from water in a storage tank to generate cooling water was proposed. Heat pipe condenser was attached with an aluminum plate and acted as a thermal radiator while its evaporator was dipped in the water storage tank. Cooling water in the tank could be produced during the nighttime and used to serve the cooling load in a room during the daytime. A heat transfer model to calculate the water temperature and the room temperature during both the nighttime and daytime was developed. The input data were ambient temperature, dew point temperature, area of the radiator, volume of cooling water and room cooling load. The experiment was setup to verify the heat transfer model. A 9.0 m² tested room with six cooling coils, each of 0.87 m² was installed at the ceiling, was constructed along with the 1.0 m³ water storage tank. A 500–2000 W adjustable heater was taken as an artificial load inside the room. A 6.36 m² radiator is installed on a 45° tilting roof of the tested room. The simulated results agreed very well with those of the experimental data. With the developed model, a simulation to find the sizing of the radiator area and the volume of cooling water for cooling water production during winter of Chiang Mai, Thailand was carried out. The cooling water was used for cooling during summer in an air‐conditioned room with different cooling loads. The parameters in terms of room temperature, radiator area, volume of cooling water, cooling load and UA of cooling coil were considered to carry out the percent of cooling load reduction. Copyright © 2009 John Wiley & Sons, Ltd.     

U型PE折叠管在工程中的应用

文章介绍了U型PE折叠管技术的工艺方法，并结合实际论述了U型PE折叠管技术的特点及优点。     

二重管无收缩双液WSST法注浆技术在基坑施工中的应用

杭州益乐路过街地下通道基坑渗水处理中，采用二重管无收缩双液WSS注浆技术施做防水帷幕。该注浆法止水迅速，持效时间长，施工简便，注浆防渗效果良好。     

考虑水管冷却的混凝土温度场的分析

分析了混凝土水管冷却问题的研究现状,总结了目前混凝土温度场水管冷却的几种算法,就温度场仿真计算原理、步骤等作了研究,从而解决了当前混凝土温度场水管冷却计算精度不足的问题。     

桐乡客运汽车站管桁架屋面设计

结合工程实例,在结构整体分析的基础上,分析混凝土结构和管桁架结构的特点,将两者较好地结合在一起。对结构构件进行合理简化,并辅以补充计算,在满足结构安全的情况下,适应复杂建筑造型的要求。为类似工程设计施工提供了参考和建议。     

垂直顶管计算方法的探讨

本文详细探讨了垂直顶管顶力的组成及其影响因素，并结合工程实践给出垂直顶管顸力的两种计算方法，以便更好地进行垂直顶管的设计和施工。     

Experimental investigation of the transient thermal performance of a bent heat pipe with grooved surface

A bent copper–water heat pipe with grooved inner surface has been investigated experimentally. A comparison between the bent and the straight heat pipes was performed at different inclination angle. Experimental results show that there is a small temperature difference between the condenser of the straight and that of the bent at the vertical orientation. The temperature difference increases as an inclination angle increases. Furthermore, the response time increases as the inclination angle increases. The thermal response of the straight to a sudden heat load is slightly faster than that of the bent. However, as the inclination angle increases to after the horizontal, the heat flux at the condensers decreases nonlinearly and the response time increases nonlinearly. A two-phase flow map has been proposed to explain the nonlinear performance of the thermal response and the heat flux, based on force balance among gravity, capillary, friction and buoyancy force acting on the working fluids. The nonlinear performance of the thermal response and the heat flux results from the capillary blocking due to formation of liquid bridge of two-phase flow. It was also found that the bent heat pipe is more sensitive to the change of the inclination angle than the straight in terms of the thermal response time and the heat flux of the condenser. The heat flux of the bent decreases faster than that of the straight after the horizontal orientation.     

浅谈顶管施工在实际工程中的应用

在阐述顶管技术特点的基础上,以重庆市某项运用顶管技术的工程案例为依托,就顶管设计采用的规范和技术标准、设计要点以及顶管施工中应注意的问题作了探讨,以推广顶管技术的应用。     

一种新型通风换气装置

针对传统新风换气机和呼吸窗的不足之处，结合住宅室内环境特点，介绍一种新型换气装置——热管节能换气窗。分析表明，热管节能换气窗具有噪声低、热回收效率高、安装方便等优点，可广泛适用于各类建筑尤其是住宅建筑。