Experimental Analysis of Building Space Constructions on Hot smoke Flow in Residential Fire

Based on the characteristics of spatial structure of residential units, the effect of building space construction on temperature raise and hot smoke flow in residential fire was analyzed on building model with simulating multiple floors and rooms. The raise and distribution of temperature indoors were mainly tested under varied location of fire sources. And, the rule of smoke flow was discussed by using the law of temperature raise, indirectly. The results indicate that the mode of smoke flows is influenced by three spatial factors which include the form of junction terminal room construction; the height of down stand above the door and the relative locations of each room. The diffusion of hot smoke is prevented effectively by the down stand of the room; the temperature difference between indoor and outdoor should be higher than that of the room without down stand. When the open direction of door in non fire room is opposite to that of the door in fire room, there is much more hot smoke.     

Biological toxicity effect of CO in fire smoke

We investigate the effect of CO on the blood rheology parameters and blood gas composition. Experiments are conducted under isothermal toxicity gas concentration non radioactive conditions. We use an exposure box 0.8 m long, 0.5 m wide, and 0.5 m high. CO     

Effect of humidity and temperature on power electric field intensity

We measure power electric field intensity at a substation in southwestern P. R. China at various humidity levels and temperatures. Measurement data and a back propagation neural network are used to construct a model of electrical field intensity responses to fluctuations in humidity and ambient temperatures. The maximum error is 0.047 5. The results show that the power electric field intensity increases as humidity rises when the temperature is constant; when humidity is a constant, temperature changes do not affect the regularity of the electric field intensity in a consistent manner regularly.     

杂交水稻繁制种隔离距离的研究

1986—1987年以不育系做受体,采用盆栽方法于开花前将受体移至粉源东南西北四个方向,每隔25米设一档次,最远距粉源275米,腊熟期统计受体的结实率。根据我们对玉米、高粱种子田隔离的研究,从定量水平求得的有无父本花粉竞争条件下污染结实率差异的统计量得知,无花粉竞争条件下的数值是有花粉竞争的三倍。本试验(无父本花粉竞争)在隔离25米,两年四个方向的平均结实率应为4.44％÷3=1.40％;隔离75米为1.20％÷3=0.40％,纯度分别可达98.52％和99.60％,均已超过国家一级杂交种纯度97％和一级亲本种纯度99.5％的标准。故此,认为国家现行隔离距离丘陵区50米以上,平湖区100米以上应更正为制种田25米以上,亲本繁殖田75米以上。     

Numerical simulation of the flow and temperature fields in an automotive exhaust muffler

By building a model of a typical exhaust muffler structure, a grid mesh was formed based on the calculation characteristic of the flow field. The software ANSYS CFX then was used to numerically simulate the flow and temperature fields in a muffler. The effects of the gas velocity and temperature variation on sound elimination performance, including the acoustics and aerodynamics performance, were analyzed. The result suggests that high velocity turbulence and high speed flow should be eliminated from muffler structures when designed. At the same time, to provide satisfactory noise elimination, pressure loss should be reduced as far as possible. The pressure loss can be decreased when reducing the perforation structure.     

A Study on Application of Air Pollution Diagnosis and Predict Model to Chongqing Urban

This paper presents results of a research project "The prediction of the Fire Smoke Flow Properties in the Building", supported by the National Natural Science Fund. The numerical model of fire smoke flow in the building and its applied computer software are outlined. The experimental results obtained from full-scale fire test are compared with the results of numerical prediction using computer software.     

Numerical Model of Hot Smoke Flow in Residential Fire

Based on the characteristics of spatial structure of residential units, the law of indoor hot smoke flow was investigated by experimental research on a platform model with multiple floors and rooms in a residential building. Three factors exerting influence on hot smoke flow in residential construction were mainly analyzed, including the relationship between the height of space and the area of single room, the size of doorway opening, and the hub space. Based on basic concepts of thermodynamics and fluid mechanics, the geometric relational model of the height of space and the area of single room impacted on filling speed of hot smoke in room was presented by conservation of mass. Moreover, under the influence of hot smoke flow, the formula of doorway opening size was developed by conservation of momentum. The results show that the fire safety of residential building should take full account of the impact of spatial structural. The indoor temperature distribution and hot smoke flow path will be controlled effectively by the design of single room size and room connectivity.     

Simulation of a steady temperature field and analysis of factors affecting a worm gear

To obtain the distribution characteristic of the temperature on the surface of worm gear, a numerical simulation using heat transfer theory, tribology theory, and mesh theory is given to calculate the heat transfer coefficient and heat flux of rolling gea     

Electromagnetic field models and their influences onthe temperature field of large hydro generator

To accurately analyze the loss and heat of large hydro generator,the finite element models of 2D steady state electromagnetic field,moving electromagnetic field and field circuit coupling are established respectively.As an example,the losses of the rotor iron and damper winding of a 36 MW tubular hydro generator are calculated.Furthermore,the influences of 3 different electromagnetic field models on the thermal sources and temperatures are analyzed by 3D finite element calculation of the temperature field.The results are compared with the test data and indicate that the precision of the field circuit coupling model is better.The losses of each damp bar are different and the heat of the damp bar at the lee side is larger than that at the windward with the full load.The maximal temperature of the rotor is located at the damper winding,instead of the field winding.The research is valuable for improving the calculation precision of the rotor losses and temperature field and enhancing the reliability of the hydro generator design and operation.     

Discussion on the Characteristics of Smoke Movement and Smoke Control Methods in a Shaft of High-Rise Building

Characteristics of smoke movement and smoke control in a shaft is a serious issue that closely related to the fire safety of high-rise building. This paper talks about the studies on the characteristics of smoke movement in a shaft of high-rise building from three aspects: the factors which influence smoke movement in a shaft, the distribution of smoke parameters and the upward velocity of smoke flow. Smoke control methods which are commonly used and the problems in engineering practice are summarized. Some methods thoughts are given to improve the efficiency of smoke control.     

Numerical Simulation for Fire Smoke Flow in a High-rise Building with Patio Space

Characteristics of smoke flow and fire spread in a patio space of a high-rise building were studied to investigate their influences on fire compartment and safety evacuation.Fire development model was established and fire scenarios were designed to simulate fire and smoke spread by CFD software numerically based on concepts of fire performance-based design in a high-rise building with double patio space,whose height are 74.65 m and 55.95 m,respectively.Simulation results show that in all fire scenarios,performance targets for safety evacuation for people in each floor was satisfied,if smoke was extracted naturally using the patio space.Hang walls mounted in corridors around the patio space prevent smoke flowing out smoothly,shorten the coming of the risk time and increase fire danger.Using chimney effect,it is preferred to adopt natural smoke exhaust method in a high-rise building with patio space.     

Analysis on temperature field of pulse current discharge in metal component with double semicircle immerged crack

The application of crack prevention techniques is badly needed in various industries. There are many practical applications, such as in space flight and aviation, shipping, military affairs and machine manufacturing. The current density distribution, temperature field distribution of flow around the crack tip and the heat affected of two cracks are derived theoretically in view of the pulse discharge in metal component with double semicircle immerged crack. A three-dimensional finite element model with semicircular embedding crack is established by finite element software ANSYS to analyze the temperature filed. The distribution law of temperature field is consistent with the results of theoretical calculations and numerical results, and the maximum temperature error and relative error are 75.560 ℃ and 3.150% respectively. By pulse discharge experiments, the crack tip melts and passivated after pulse discharge.     

杂交蓝莓‘兴安1号’抗寒能力分析

为解决野生蓝莓抗寒性评估问题,选用‘兴安1号’杂交蓝莓与父本美国矮丛蓝莓、母本野生蓝莓为材料,采用盆栽实施梯度防寒,对其在低温胁迫下的各项生理指标进行测定,结合隶属函数法对3个蓝莓品种的抗寒性进行综合评估。结果表明,在低温胁迫条件下,3个蓝莓品种的电导率、MDA含量、H₂O₂含量、O₂^-速率、ABA含量与对照相比显著提高,差异达到极显著水平;MDA含量、相对电导率、O₂^-速率的权重值较大,抗寒性由强到弱表现为‘兴安1号’、野生蓝莓、美国矮丛蓝莓,田间试验与抗寒性综合评估结果趋于一致。     

Three-dimensional Large Eddy Simulation of Smoke Flow during Indoor Fire

Indoor fires are quite dangerous,claiming many casualties and resulting in great property loss.Using Computational Fluid Dynamics(CFD),a three-dimensional large eddy simulation model of smoke flow is set up.Through the simulation of smoke flow,the theoretical basis is provided for controlling a fire in multiple rooms,thereby saving people.The results of simulation show that high temperatures and thick smoke exist near the fire,and the probability of combusting other tinder will increase.Moreover,there are close relationships between fire and ventilation.The latter can lower the average temperature and speed up the spread of smoke flow and toxic gases,providing conditions for the further development of indoor fire.Moreover,from both the simulated calculation and physical measurement,it is shown that indoor fires and their temperature distribution and smoke concentration are influenced by the fire power and the room size.The results from calculation and measurement are quite consistent.     

Analysis of temperature field around groundwater heat source wells under coupled thermal conduction and groundwater advection conductions

For studying the effect of the groundwater heat source wells working on the temperature field,the Comsol Multiphysics is used to build a three dimensional numerical model which couples thermal conduction and groundwater advection conductions. Some conclusions have been concluded by contrasting five different conditions that under different quantities of heat exchanged water put into the recharge well and a detail analysis of one. With the quantity of recharged heat exchanged water becoming larger, the influence radius expands and the heat surface between the two wells transfers more quickly to the pumping well. Temperature of the region close to the recharge areal increases obviously in early stage,while temperature of the region not so close to the recharge area ismore influenced in later stage. The temperature is closely relate to the seepage velocity and has nothing to do with position. Influence radius is almost proportional to seepage velocity.     

Modeling and simulation of the upper limb artery system using three section electric network model

A three section electric network model is built for human upper limb arterial system according to the Windkessel model. Blood pressure waveform of brachial artery is inputted into the electric network model. The state space equations of the electric network model are refined by using the state space analysis and solved numerically by the fourth order Runge Kutta method to obtain the blood pressure and flow waveform of radial artery. Effects of changes of the electric network model’s parameters on the blood pressure and flow waveform are also analyzed in normal and different pathological conditions(arteriosc lerosis and hypertension). The results of simulation show that the parameters of the model can well reflect the physiological significations of the upper limb arterial system; the analytic and computational methods are of fairly high precision and fast convergence for the model; and the model can simulate effectively the hemodynamic characteristics of upper limb arteries under normal and different pathological conditions.     

水稻亚种间杂种F1低温敏感不育基因的差异显示

为研究水稻籼粳杂种低温下的育性特点和特异基因表达,以孕穗期白天24℃,夜晚20℃的低温和正常温度下生长的籼粳杂种02428/3037 F1及其亲本幼穗为材料,开花期对亲本、处理和对照的花粉育性分别进行了观察,种子收获后考察了其结实率。结果表明,与对照相比,白天24℃夜晚20℃的低温处理使杂种的花粉育性和结实率明显降低,但对亲本的花粉育性和结实率影响不大。用12条锚定引物和18条随机引物共216对引物组合对总RNA反转录后的cDNA进行了PCR扩增,共有35条在处理和对照间可重复扩增的表达差异的条带。对克隆后的差异条带进行了测序和Blast,发现这些差异片段与一些幼穗发育的EST有很高的同源性,同源性均在99%以上。其中一个与位于水稻第一号染色体的过氧化物酶基因的部分片段有100%相似性,另一个与位于第十二号染色体上的蛋白磷酸化酶基因有99.99%的同源性,分别与两个LTSS 基因所在的染色体一致。Southern杂交显示它们均为单拷贝片段。这些基因的表达与关闭与籼粳杂种低温敏感不育可能有密切关系。     

蠕变模型对约束钢梁抗火性能分析的影响

钢材在高温和荷载作用下产生明显蠕变变形,影响火灾中结构的变形和受力性能。现有的蠕变模型较多,但没有一个广泛适用的蠕变模型。不同的蠕变模型对钢结构抗火分析结果有很大影响。为了量化蠕变模型对约束钢梁抗火性能分析的影响,对5种常用的蠕变模型进行了对比分析。采用编写的约束钢梁计算程序,分别计算5种蠕变模型下约束钢梁的抗火性能并与试验数据进行对比。结果表明,采用Norton蠕变模型的计算结果与试验数据吻合最好。最后对影响约束钢梁抗火性能参数进行了研究,研究发现,Harmathy蠕变模型对约束梁抗火性能分析结果影响最大;不同蠕变模型对不同荷载比、约束刚度下的约束钢梁抗火性能影响程度均不同。     

寒冷地区建筑负荷对围护结构热工参数的敏感性分析

为研究建筑围护结构属性对同一热工分区不同城市节能建筑负荷影响的敏感性,以同属于寒冷地区的兰州和郑州为研究目标所在城市,在节能65%的前提下将4种外墙、3种外窗和4种窗墙比进行组合得到了48个可能的办公建筑围护结构计算房间。分别计算了这些房间的冷负荷、热负荷和全年总负荷并分析了各热工参数对负荷的影响。通过与基准房间负荷对比,获得了具有不同热工性能的计算房间的节能率及最优的办公建筑围护结构。     

Physical simulation of fluid field and structure optimization in two-strand tundish

The influence of the structure and location of dam and weir on fluid flow state in a two-strand tundish is studied, and a set of optimal structure, combining with the average residence time calculated from RTD curve, is obtained. The result indicates that the fluid flow state can be changed and the path of the fluid flow can be prolonged as well as the average residence time is improved after using dam and weir. But there are some dead zones after fluid passed through the dam and weir. Combination scheme of No. one dam and weir is better than the others. Its average residence time is 299 s and the volume fraction of dead zone is 31.0%. After the optimization of flowing control parameters in tundish, the best case is that the distance between dam and weir is 290 mm and the distance between weir and the long nozzle is 383 mm. The longest average residence time is 351 s and the minimum volume fraction of dead zone is 19.0% under the above situation. Compared with that of no dam and weir, the average residence time increases by 65 s and the dead zone volume fraction decreases by 15.0%. Based on Newton formula, the calculated results show that the inclusions with diameter larger than 17.5 μm can float up within 351 s under this optimization situation.