温度分层型水蓄冷槽斜温层的动态特性模拟

针对温度分层型水蓄冷槽提出了一种新型布水器开孔方式,研究了流量为1.0 m3/h时开孔角度分别为60°、90°、120°三种情况。采用计算流体力学(CFD)的方法分析了布水器的开孔角度对温度分层的影响,模拟在充冷过程中垂直高度方向的温度分布和蓄冷槽底部的速度分布情况,并进行了比较分析。结果表明,在开孔角度为90°时,布水器出流最为均匀,斜温层厚度最小,布水器性能最好。     

实用节能技术—水蓄冷技术介绍

本文简述了水蓄冷技术应用中目前常用的水蓄冷罐形式及其蓄冷方法，并着重论及自然分层方法中散流器的设计和蓄水罐的设计。     

实用节能技术－水蓄冷技术介绍

本文简述了水蓄冷技术应用中目前常用的水蓄冷罐形式及其蓄冷方法，并着重论及自然分层方法中散流器的设计和蓄水罐的设计．     

空调水蓄冷温度分层动态特性研究

空调水蓄冷适合常规制冷机组进行,不需要更换已有的空调设备,初投资和运行费用低,操作简单。对空调水蓄冷温度分层的特性进行分析,建立相应的数学模型,模拟了水蓄冷罐的温度分布规律。该模型可为空调水蓄冷系统的设计和运行提供理论依据。     

温度分层型水蓄冷罐的仿真研究

介绍了温度分层型水蓄冷罐的仿真研究。阐述了计算模型、计算条件和计算结果，详细分析了温度分层型水蓄冷罐的斜温层，讨论和评价了残留斜温层对后续过程的影响。对不同蓄冷温度差和不同流速条件下的斜温层厚度进行了定量分析和对比，以及回归分析。     

浦东机场能源中心水蓄冷运行方式改进方案

随着空调蓄冷技术的不断发展,在一些分布式能源中心项目中,空调水蓄冷作为空调蓄冷的一种新方式,已逐渐展现出其在节能效果、经济效益和社会效益中的强大生命力和广阔市场。主要探讨了如何避免在自然分层水蓄冷系统的运行过程中,由于运行方式等问题造成水蓄冷罐内斜温层过大,从而导致能耗的浪费以及蓄冷系统利用率下降等一些问题。阐述了通过改进运行控制方式,使斜温层稳定在合理范围内,以确保整个水蓄冷系统安全、高效地运行。     

温度分层型水蓄冷槽布水器的斜温层试验分析

为了分析温度分层型水蓄冷槽中布水器的开口间距和直径对温度分层的影响,对四种不同开口间距的布水器在充放冷过程中的温度分布以及两种口径布水器在充冷时蓄冷槽的温度分布。试验结果表明,孔口开孔直径和开口间距对温度分布有很大的影响,在相同流量下,空口开口直径大的布水器比开口直径小的布水器形成的斜温层更薄、更稳定;开口间距与开口高度比值在1～2之间的布水器的蓄冷效果较好。     

空调蓄冷方式的比较

本文介绍了电网调峰的几种方式，蓄冷空调在电网调峰中的重要地位，各种蓄冷方式和特点，并对水蓄冷和冰蓄冷的应用条件进行了比较，指出了上海地区水蓄冷技术的应用领域。     

水蓄冷空调设计方法探讨

叙述了在各种气候条件下不同形式规模和用途的建筑中，以水蓄冷空调冷负荷特性为出发点的3种可能性，设计了多种技术方案，分析了各种水蓄冷空调系统的技术经济效益，提出了针对各种不同电价政策可选择的方案。     

蓄水槽的形状因素对自然分层水蓄冷影响的模拟分析

针对现今水蓄冷槽占地面越来越小、高度越来越高的特性,以及就地采用不规则形状消防水池的特点,通过CFD(FLUNET软件)模拟来分析不同高度和不同形状的蓄水槽对斜温层及有效蓄冷率的影响,对提高水蓄冷的利用率具有一定的价值。     

The exergy of stratified thermal energy storages

The performance of energy and exergy analyses of TES systems incorporating thermal stratification are described, along with the resulting insights and benefits. Six temperature-distribution models for stratified TESs are considered (linear, stepped, continuous-linear, general-linear, basic three-zone and general three-zone) which facilitate the evaluation of energy and exergy contents. The selection of a particular distribution is seen to involve a trade-off between result accuracy and calculational effort. It is shown using the temperature-distribution models how improving stratification can increase TES efficiency, and how the use of stratification can increase the exergy storage capacity of a thermal storage. Consequently, exergy analysis is shown to provide illuminating and meaningful assessments and comparisons of such TES systems that can assist in improving and optimizing designs. It is hoped that the results will facilitate the development of standardized exergy-based methodologies for the evaluation and comparison of stratified TES systems.     

LIMITATION OF BOUNDARY LAYER ANALYSES FOR BUOYANT CONVECTION IN STABLY STRATIFIED FLUIDS

Vertical buoyant convection in stably stratified fluids is revisited. The limitation of boundary layer analyses for such flows is quantified. This is accomplished by comparing the results of the present boundary layer numerical study with the published experimental measurements, and full numerical simulations. It is shown that boundary layer analysis underpredicts the heat transfer rates. This is explained with reference to the flow and thermal fields. The boundary layer results are shown to be inadequate for such characteristics as flow reversal and temperature defects. The underlying physical mechanisms are discussed.     

层式下吸式秸秆气化机组及其应用

结合层式下吸式秸秆气化机组在农村集中供气系统中的实际应用，介绍了气化炉的床层高度和原料搭配对产气量、燃气热值及焦油含量等主要性能指标产生的影响，阐述燃气净化所用材料的利弊，对机组主要组件的功用简单予以介绍，对机组使用中的常见问题加以说明，对各检测数据进行分析比较，为研究机组性能提供依据，从而促进技术不断提高。     

Experimental study of thermally generated reverse stratified layers in a fire tunnel

The behavior of thermally generated stratified layers in a fire tunnel in the presence of ventilating-air flow is investigated experimentally. In the present work the hot combustion products are produced using burners in a high temperature wind tunnel so that measurements can be made under steady conditions. At sufficiently low ventilation velocity, a hot reverse stratified layer is formed near the ceiling and flows against the ventilation. The present paper reports measurements of the mean velocity and mean temperature distributions across the tunnel cross sections where the reverse stratified layer exists. Some probing of the plume zone is also made to understand the formation of stratified layers when a fire occurs in a ventilated tunnel. The factors that are considered are the velocity and temperature of the stratified layer, the ventilation flow velocity, and the angle of inclination of the channel. The lengths of reverse stratified layers are determined under various test conditions.     

Source Rock Evaluation of The Eocene Shales in the Gökçesu Area (Bolu/Turkey)

Abstract

Hydrocarbon potential of oil shale samples from the Gökçesu basin in Bolu, Turkey, was evaluated on the basis of organic geochemical, organic petrographic, gas chromatography, and thin-layer chromatography techniques. Organic materials were found to be oil-producing type (Type I and II kerogen). Thermal maturities, that indicate diagenetic and early mature oil formation stage, were determined with pyrolysis (Tmax), production index (PI), and spore color index (SCI) analyses. The amount of organic material ranging between 0.21 and 15.89% reveals that the unit has variable source rock potentials from weak to perfect. The productivity of the basin was probably high and organic matter preservation was enhanced by a stratified water column. As the basin began to fill with sediment and become shallower, TOC and HI values declined, as the basin water was better oxygenated and preservation conditions declined. On the basis of geologic data, organic geochemical analyses and organic petrographic studies, organic facies of Eocene shales is of AB and B types.     

Energy and exergy analyses of cold thermal storage systems

This study deals with the assessment of the thermodynamic performance of cold thermal storage systems using exergy and energy analyses. Several cases are considered, including some storages which are homogeneous, and others which undergo phase changes. In some cases the storages are stratified. A full cycle of charging, storing and discharging is considered for each case. Four cold thermal storage cases are presented in an illustrative example. The results demonstrate that exergy analysis provides more realistic and accurate assessments of the efficiency and performance of cold thermal storage systems than those given by the more conventional energy analysis. In addition, exergy analysis is conceptually more direct since it treats cold as a valuable commodity. It is concluded that the potential usefulness of exergy analysis in addressing and solving cold thermal storage problems is substantial. Copyright © 1999 John Wiley & Sons, Ltd.     

基于分区建模的大空间分层空调负荷随分层高度变化的研究

以某坡屋顶大空间建筑为研究对象,利用eQUEST软件,提出了空调区和非空调区分区的建模方法,依据所建模型分析全室空调和不同分层高度时夏季分层空调峰值冷负荷特性.模拟结果表明,分层空调形式的负荷比全室空调的减少30%以上,夏季空调峰值负荷随分层高度增加近似线性增加.比较模拟负荷与常规分层空调负荷计算结果发现,两者相对误差小于3%,说明基于动态能耗模拟软件分区模拟大空间分层空调负荷的方法合理.     

A numerical study of laminar flame speed of stratified syngas/air flames

Numerical simulations are performed to study the flame propagation of laminar stratified syngas/air flames with the San Diego mechanism. Effects of fuel stratification, CO/H₂ mole ratio and temperature stratification on flame propagation are investigated through comparing the distribution of flame temperature, heat release rate and radical concentration of stratified flame with corresponding homogeneous flame. For stratified flames with fuel rich-to-lean and temperature high-to-low, the flame speeds are faster than homogeneous flames due to more light H radical in stratified flames burned gas. The flame speed is higher for case with larger stratification gradient. Contrary to positive gradient cases, the flame speeds of stratified flames with fuel lean-to-rich as well as with temperature low-to-high are slower than homogeneous flames. The flame propagation accelerates with increasing hydrogen mole ratio due to higher H radical concentration, which indicates that chemical effect is more significant than thermal effect. Additionally, flame displacement speed does not match laminar flame speed due to the fluid continuity. Laminar flame speed is the superposition of flame displacement speed and flow velocity.     

Mixture distribution measurement using laser induced breakdown spectroscopy in hydrogen direct injection stratified charge

Reduction in cooling loss due to the heat transfer from burning gas to the combustion chamber wall is very important for improving the thermal efficiency in hydrogen engines. The previous research has shown that the direct injection stratified charge can be a technique to reduce the cooling loss and improve thermal efficiency in hydrogen combustion. For effective reductions in cooling loss by the stratified charge, it is very important to know the relation between the fuel injection conditions and mixture distribution. The current research employs the laser induced breakdown spectroscopy as a method to measure the hydrogen concentration distribution in the direct injection stratified charge. Measurement of instantaneous local equivalence ratio by the method clears the characteristics of mixture formation in hydrogen direct injection stratified charge. This research also tries to actively control the mixture distribution using a split fuel injection.