大地震前后地温、降水及浅层热流通量场的结构特征

利用中、蒙两国气象站的地温和降水资料，分析了近４０年来地温资料较密的华北及其北邻地区６次大地震前后的地温场及降水场的分布形势及其演变特征．在地震前半年到一年的时间里浅层地温场的演变特征是：未来震中区为正地温距平区，周围为较大范围的负距平带环绕，且正距平区呈逐渐增大增强的趋势，直至地震发生；降水场的特征是：震前１－５个月左右在大面积干旱的背景下，未来震中区同时存在一小范围的多雨中心．设计了一种利用浅层地温资料滤去来自上层大气的影响，获得浅层以下地热信息的方法．计算了能够反映深层地热信息的地表浅层热流通量，发现地震前地表以下存在着一个三维热柱结构，即中心热流向上，周围向下．

大热流通量条件下原位合成Fe-TiC复合材料的研究

首次应用Gleeble热模拟机研究Fe-Ti-C体系在大热流通量条件下原位合成Fe-TiC复合材料。通过压坯在加热升温过程所反映出的特点,结合热力学计算,以及对产物的X射线衍射分析(XRD)、扫描电镜(SEM)以及能谱分析(EDS)等的研究分析,结果表明:在大热流通量下,可以大幅度地降低合成反应起始温度,且反应完全。在实验研究条件下,Fe-Ti-C体系可在394℃的低温条件下发生合成反应。合成的产物除了分布在铁基体中的小颗粒TiC外,还有少量的Fe2Ti。此研究结果为低温合成Fe-TiC复合材料提供了一条新途径。

温室温度和热流通量的动态模拟

提出了温室气候的动态模型,在模型中考虑到了温室内三层土壤、作物层、室内空气和覆盖物之间的传导、对流、太阳辐射和热辐射以及潜热交换,在此基础上,研究了比利时典型天气条件下温室内的温度和热流通量的变化,认为室内气温主要取决于室外气温、太阳辐射和热辐射,所以,对玻璃温室的对流传热损失和塑料大棚的热辐射损失必须引起足够重视。

热湿气候地区湿传递对吸放湿墙体热湿性能的影响

以墙体中的空气含湿率和温度为驱动势建立了多层墙体的一维瞬态热湿耦合传递方程,将用此方程计算出的值跟用忽略湿传递的导热方程计算出的值进行对比得出湿传递对墙体热湿性能的影响。结果表明,对于吸放湿墙体而言,湿传递对墙体的热湿性能有着非常重要的影响。在进行墙体传热计算时,如果忽略墙体中的湿传递会产生较大误差,不能精确的预测墙体内的温度分布情况,并且导致计算出的空调负荷偏小,进而影响到空调的实际效果。

低温地板辐射采暖系统的传热分析与仿真

建立了低温地板辐射供暖系统的传热过程的数学模型,用有限元法对数学模型进行求解。以一个动态仿真程序得出了不同供回水平均温度和排管间距下的地板表面最高温度和单位面积的热流量,阐明了系统的舒适和节能特性,为工程设计提供了理论依据。

动态地幔柱尾管结构

动态地幔柱模式被广泛用于讨论地球科学中的一些重要课题，如巨大火成区的成因，冈瓦纳古陆解体的原因，板块内中小尺度动力过程的驱动因素等．但是这个基于实验研究而建立的模式中，忽略了地幔柱尾管特征及其作用．地幔柱尾管内温度和速度分布是研究地幔柱上升过程的必要条件．本文从控制尾管结构的基本方程出发，给出了一个定常轴对称地幔柱温度和速度分布的近似分析解．从而得到尾管结构的基本特征：影响尾管内温度分布的主导因素是地幔柱的热流通量，而尾管内上涌速度的大小则不仅取决于热流通量，主要是取决于地幔粘度随深度的变化方式．结果表明，对弱地幔柱，尾管的热损失可能是不可忽略的，而对强地幔柱，径向质量传递可能是不可忽略的.

新型地板辐射供冷暖系统的理论研究

提出了一种新型地板辐射供冷暖系统,通过综合利用墙体和地板的导热,仅将金属管路布置在踢脚线内,并采取强化传热措施,即可满足室内供能需求。建立了该系统的理论模型,并用有限元方法对其传热性能进行了数值模拟。研究结果表明:该系统供能效果良好,冬季采用40℃C供暖介质便能满足保温的节能后居住建筑的供冷暖需求,夏季用10℃制冷介质即可满足该房间的制冷需求;地板辐射面提供热量约占60%;系统供能能力受埋管管径、介质温度及强化传热的材料等因素的影响,其中介质温度的影响最为明显。

Analysis of heat pulse signals determination for sediment-water interface fluxes

The heat pulse signal is analyzed in a new way with the goals of clarifying the relationships between the variables in the heat transfer problem and simplifying the procedure for calculating sediment-water interface fluxes J. Only three parameters x0 λand pc l are needed to calculate J by the heat pulse data for this analysis method.The results show that there is a curvilinear relationship between the peak temperature arrival time and sediment-water interface fluxes and there exists a simple linear relationship between sediment-water interface fluxes and the natural log of the ratio of the temperature increase downstream from the line heat source to the temperature increase upstream from the heat source.The simplicity of this relationship makes the heat pulse sensors an attractive option for measuring soil water fluxes.

数字模拟

Comparison of field results and digital simulation results of voltage-sourced converter-based FACTS controllers；COMPENSATION FOR LOAD AND SPEEDVARIATION OF SELF-EXCITED INDUCTION GENERATOR；Coupling experimental design-digital simulation of junctions for the development of complex tolerance chains；Critical heat flux of ice accretion along a fine wire immersed in cold air stream with water spray (digitalsimulation on effects of droplet diameter profile on criticalheat flux)；Cushioning of pneumatic cylinders。

Variability of Surface Sensible Heat Flux over Northwest China

The present study documents the variability of surface sensible heat flux over Northwest China using station observations for the period 1961 2000.It is found that the afternoon and nighttime sensible heat flux variations are remarkably different.The variability of the instant flux in the afternoon is much larger than in the nighttime.The afternoon and nighttime flux anomalies tend to be opposite.The diurnal and seasonal dependence of sensible heat flux variations is closely related to the diurnal cycle of mean land-air temperature difference.The relationship of sensible heat flux with land-air temperature difference based on the instant value differs from that based on the daily mean.The present study indicates the importance for the models to properly simulate mean land-air temperature difference and its diurnal and seasonal variations in order to capture surface sensible heat flux variability over Northwest China and predicts its plausible impacts on climate.

Study on the distribution of strata rock temperature around a driving head with auxiliary ventilation

The distributions of strata rock temperature around a driving head with auxil- iary ventilation were analyzed theoretically based on a program which was developed by the authors to predict the thermal environmental conditions in a development heading with forcing auxiliary ventilation. The influences of wetness of the airway surface were dis- cussed on the cooled zone of the strata rock and on the temperature distribution in the surrounding rock. It is shown that the advancing speed and driving time have little influ- ence on the temperature profile in front of the working face of a driving airway, and the rock temperature 1.5 m ahead of the working face can be taken as the virgin rock tem- perature.

A high-top version of IAP-AGCM:Preliminary assessment and sensitivity IAP-AGCM

Extending the atmospheric model top to high altitude is important for simulation of upper atmospheric phenomena,such as the stratospheric quasi-biennial oscillation.The high-top version of the Institute of Atmospheric Physics Atmospheric General Circulation Model with 91 vertical layers(IAP-AGCML91)extends to the mesopause at about 0.01 hPa(~80 km).The high-top model with a fully resolved stratosphere is found to simulate a warmer stratosphere than the low-top version,except near the South Pole,thus reducing its overall cold bias in the stratosphere,and significantly in the upper stratosphere.This sensitivity is shown to be consistent with two separate mechanisms:larger shortwave heating and larger poleward stratospheric meridional eddy heat flux in the hightop model than in the low-top model.Results indicate a significant influence of vertical resolution and model top on climate simulations in IAP-AGCM.

Impact of Convective Momentum Transport by Deep Convection on Simulation of Tropical Intraseasonal Oscillation

This paper focuses on the impacts of convective momentum transport(CMT) on simulations of the tropical intraseasonal oscillation(TIO) in SAMIL. Two sets of experiments are performed, which give different reality of the Madden-Julian Oscillation(MJO). The Tiedtke cumulus parameterization scheme is used for all experiments. It is found that simulations of the TIO can be influenced by CMT, and the impacts on the simulated TIO depend on the model capability in simulating the MJO. CMT tends to have large influences to the model that can simulate the eastward propagation of the MJO. CMT can further influence the long-term mean of zonal wind and its vertical shear. Zonal wind suffers from easterlies biases at low level and westerlies biases at upper level when CMT is introduced. Such easterlies biases at low level reduce the reality of the simulated tropical intraseasonal oscillation. When CMT is introduced in the model, MJO signals disappear but the model's mean state improves. Therefore, a more appropriate way is needed to introduce CMT to the model to balance the simulated mean state and TIO signals.

Improvement of Critical Heat Flux Performance by Wire Spacer

In order to investigate the coolability of a tight lattice core in BWR （boiling water reactors）, an experiment of CHF （critical heat flux） was conducted using a single heater pin flow channel with and without a wire spacer with the mass flux ranged from 200 kg/（m2.s） to 600 kg/（m2·s）, the inlet temperature from 50 ℃ to 90 ℃ at the pressure of 0.1 MPa. The results of CHF values were compared between two different types of heater pin with and without the wire spacer. The heat removability of flow channel was improved by the wire spacer in comparison with the heater pin flow channel without the wire spacer. The CHF value was higher in the heater pin channel with the wire spacer than in that without the wire spacer.

Analysis of disagreement between numerically predicted and experimental heat transfer data of impinging jet

The method of numerical simulation was applied to investigate the effects of jet impinging plate thickness and its thermal conductivity on the local heat flux distribution along the impinging plate. The results show that the two factors have great effects on the heat flux distribution. The non-uniformity of the local heat-flux on the impinging plate surface gets more profound as the plate becomes thicker and thermal conductivity gets larger. When Reynolds number is 5000, the ratio of nozzle-to-plate spacing to nozzle diameter is 5 and thermal conductivity is 16W/(m·K), and even for the plate with only 25μm in thickness, the non-uniformity of the heat flux cannot be neglected. When the plate thickness is 50 μm, only when thermal conductivity is as small as 1W/(m·K), the heat flux curve can be approximately treated as an iso-heat-flux boundary. In the experimental research, a real non-iso-heat-flux boundary is treated as an iso-heat-flux boundary, which would result in under-estimated Nusselt number value in the stagnation zone and an over-estimated value outside. Such an experimental Nusselt number distribution is taken to evaluate turbulent model, and the conclusion would be drawn that the turbulent model over-predicts the stagnation heat transfer. This is one of the important reasons why many literatures reported that k-ε turbulent model dramatically over-predicts the impinging jet heat transfer in the stagnation region.

Investigations on the Heat Flux Rates in Superheated Water Jet Evaporators

When a liquid undergoes sudden reduction in the surrounding pressure below its saturation pressure, the liquid then enters in a metastable state. In order to regain equilibrium, part of the liquid evaporates quickly in a phenomenon called ＂flash evaporation＂, and the excess sensible heat contained in the liquid is converted into latent heat of vaporization. Therefore, temperatures of both the liquid and the generated vapor decline to the saturation temperature for the reduced pressure. As the heat and mass transfer occur in direct contact between the liquid and its own vapors, the process involves a very high heat transfer rate which makes it suitable for exchanging heat between sources of relatively small temperature difference. Moreover, dispensability of the heat exchange surfaces in this process is a considerable advantage as these surfaces constitute major part of the total system expenses in addition to the associated maintenance problems, especially when dealing with corrosive fluids such like seawater in the thermal desalination processes and in the OTEC （ocean thermal energy conversion） systems. This paper reports on the heat flux variation profiles during the flash evaporation of superheated water jets at various flow conditions. Heat flax was found to grow with time attaining a peak value before it starts to decrease monotonically.

A General Thermal Equilibrium Discharge Flow Model

Based on isentropic flow and thermal equilibrium assumptions, a model was derived to calculate discharge flow rate, which unified the rules of room temperature water discharge, high temperature and high pressure water discharge, two-phase critical flow, saturated steam and superheated steam critical flow, and gave a method to calculate critical condition. Because of the influence of friction, the entropy is increased in the actual discharge process, and the discharge flow rate in thermal equilibrium condition can be obtained by the original model multiplied by an appropriate correction coefficient. The model calculated results agreed well with the experiment data of long nozzle critical flow.

Laminar Heat Transfer Modeling and Investigation of Thermal Dispersion in a Flat Plate Heat Exchanger： Estimating Heat Transfer Coefficient, Heat Flux and Nusselt Number

PHEs （plate heat exchangers） are among the most common thermal equipments in diverse industries particularly in oil and gas companies. This wide usage is obviously due to significant benefits of these heat exchangers over other types. In this article, a behavioral analysis of heat transfer in fiat plates of these heat exchangers in laminar flow situation through CFD （computational fluid dynamics） simulation using FLUENT 6.3.26 software is done. The study reveals results graphically based on fluid＇s behavior in co-current and counter current flows and discusses thermal indexes consisting of heat transfer coefficient, Nusslet and total heat flux in both conditions. Eventually, a comparison via the graphical results is presented between the two types of flow directions.

Experimental Study of Heat Transfer for a Rotating Cylinder Water Jet Impingement Quenching

Transient heat transfer has been experimentally investigated for subcooled water jet impingement quenching of a hot rotating stainless steel cylinder. Temperatures beneath the impinged surface were measured during quenching and used to estimate surface temperature and surface heat flux by using a developed numerical inverse solution of heat conduction. Heat flux reached its maximum value just after the WF （wetting front） （visible leading edge of boiling region） started moving from stagnation towards the circumferential region. WF moved in a non-uniform manner in angular direction on the hot rotating surface. With the increase of surface velocity, heat flux decreased. Higher surface velocity moved away the produced vapor bubbles and reduced the solid-liquid contact time which made it one-dimensional heat conduction from multi-dimensional, that reduced heat flux. The generated boiling curve from the estimated heat flux showed a reasonable agreement with existing studies. The surface maximum heat flux （maximum value in each cycle） distribution trend with radial position is entirely comparable with the static surface critical heat flux in literature. An explosive to a sheet like flow patterns were observed with the decrease of surface temperature. The flow patterns were followed by the intensity of sound during quenching.