查询词典 heat transfer

Single-phase forced convective heat transfer inside tube is an important research realm in the technology of heat transfer enhancement. It plays an important part in saving energy and decreasing the volume and weight of heat exchanger.

管内单相流体强制对流换热是强化传热技术的重要研究领域，其在降低换热器的能源消耗，减小换热器的体积和重量起着十分重要的作用。

However, based upon the results indicated above the heat transfer rates with certain combinations of the oscillation amplitude and Rayleigh number or Grashof number are possibly smaller than that of the stationary condition. Then the critical oscillation frequency could be regarded as a criterion of whether the heat transfer rate of the heat surface subject to a oscillation motion being larger than that of the stationary state or not .

虽然一般的观念大都认为存在振动的热表面其热传的效果会比没有振动的情形下要好，但是由研究结果得知，在不同的振幅与雷利数或葛瑞秀夫数搭配时，加入振动后的热传现象仍可能比没有振动时的热传效率差，也因此可以定义且找出临界振动频率以提供研究振动热传者之参考。

With a constant space and different duty ratios, two conditions with high heat transfer performances emerged mainly due to the different degrees of influence of the heat transfer surface area and the rib thickness on the heat exchange performance.

以换热系数进行比较，当占空比为83％左右时，热沉表面温度最低，换热性能最佳；当间距恒定不变而占空比不同时，会出现两个换热性能较好的情况，主要是由于换热表面积和肋片厚度影响换热性能的程度不同。

By setting up the mathematical models of the regulating objects （combusting heat transfer, heat utilization and storage, superheater and main steam pipe line）, by combining heat transfer function of regulating system and by selecting method of setting PID accoding to set attenuation index object, the corrections among PID and pulverized coal＇s caloric values are found. Now the PID can be set according to caloric values of the pulverized coal burned in the unit and the automatic control can be put into operation.

通过建立调节对象四个环节（燃烧传热过程、热量的利用和储存过程、过热器、主蒸汽管道）的数学模型，结合调节系统的传递函数，选用按给定衰减指数设定PID参数的方法，找出PID参数与煤粉热值的关系式，最终达到在机组燃烧不同热值的煤粉时可依据该方法设定不同的PID参数、并都能投自动的目的，从而有利于提高机组的稳定性，并可节约煤粉。

The main works are listed as follows:1 Thermal Computi ng model of steam pipe network were built with good match to actual operating dataThe thermal calculation model of steam pipe network was established according to the steam pipe network heat transfer characteristics and the thermal equilibrium principle,. It includes steam temperature drop expression, the expression of per unit length heat loss when steam pipe laying in different ways and total heat transfer coefficient expression.

该模型由管内蒸汽温降方程、不同敷设方式蒸汽管道的单位长度散热损失方程、总传热系数方程等组成，利用散热损失计算公式对钢套钢蒸汽保温管道不同敷设方式、不同管径的散热损失等总传热系数的影响因素进行了分析，计算结果表明三方程联合求解提高了新建蒸汽管网热力计算的准确度，可用于新建蒸汽管网的热力计算。

Results from the experiment on an EHD experiment bench show that condensation heat transfer in a horizontal tube responds strongly to the EHD technique; the effect is greater for lower heat flux but lesser for higher heat flux; the enhancement coefficient is proportional to the exerted voltage for a constant heat flux and reaches as high as 156% under the conditions described in this paper.

在电流体力学强化传热试验台上进行了水平管内凝结传热的强化试验研究，结果表明，EHD技术对水平管内的凝结传热有明显的强化效果；低热流密度时，强化效果较好，增大热流密度时，强化效果减弱；热流密度维持不变时，强化系数随强化电压的升高而增大；在本试验条件下，对凝结传热的最大强化系数为 1 5 6%。

Based on the thermodynamic analysis of heat transfer process between water jet and the blade surface, the differential equations of heat convection and differential equation of steady heat conduction between water jet and the blade surface are established. Power expression of heat exchange and temperature field expression of the blade are derived.

根据对水射流与刀片间传热过程的热力学分析分别建立了水射流与刀片表面对流换热微分方程组和热源与刀片间的稳态导热微分方程，推导出水射流对刀片的换热功率表达式和刀片内温度场表达式。

In the analysis, firstly, the flux boundary condition is used to simulate the frictional heat resource between wheel and rail. The non-steady heat transfer between the contacting surfaces of the wheel/rail, heat-convection and radiation between the wheel/rail and the ambient were all taken into consideration. Therefore, a heat coupling model of the wheel/rail in rolling/sliding is put forward to calculate the frictional temperature rise in the wheel and rail. Secondly, after the temperature distribution of wheel/rail, due to friction, is calculated, substitute the thermal load with equivalent fictitious body force and boundary distributed force loaded on the nodes of the corresponding elements. The wheel-load is applied to the center of the wheel.

首先，用热流边界条件模拟轮轨接触界面的摩擦热源，考虑轮轨间的非稳态热传导、轮轨自由表面与环境的热对流、热辐射的影响，建立轮轨滚动接触热耦合有限元计算模型，分析计算轮轨滚、滑工况下的摩擦温升；其次，以求得的轮轨温度场结果作为求解轮轨应力场的已知条件，轮载以集中力形式直接加载于轮心处，将摩擦温升引起的热载荷等效为假想体力和热边界面力，施加于相应的单元节点上，建立了轮轨热—机械载荷耦合作用的热弹性平面应力模型，分析热—机械载荷作用下的轮轨应力场。

A numerical study of the heat and mass transfer process of the solution absorption and the moving out of absorption heat through heat pipe in heat pipe-type falling film absorber are presented.

对第二类吸收热泵热管式降膜吸收器溶液降膜吸收传热传质并通过热管移出吸收热的过程进行了数值研究。

The oil-quenching tank uses the steel plate structure, has the square shape, the rectangle, the circular, in the fuel tank the installment has the electric heating tube, outside the trough the installment has the oil pump, the stainless steel disc heat interchanger, the automatic oil constant temperaturecontrols the warm cabinet, its principle of work: When the work piece enters fuel tank quenching to cause frequently the oil temperature elevates, the oil pump starts to work, sucks in the stainless steel disc heat interchanger fuel tank's in high temperature oil, this time cools the circulating waterto put through automatically, carries on the heat transfer through disc heat interchanger's multi-layer stainless steel plate trough, causes the quenching oil which the process cools to return to the oil-quenching tank again, so moves back and forth the circulation, achieves the fuel tank to decreasetemperature the goal.

淬火油槽采用钢板结构，有方形、长方形、圆形，油槽内安装有电加热管，槽外安装有抽油泵、不锈钢板式换热器，自动油恒温控温柜，其工作原理：当工件频繁进入油槽淬火引起油温升高时，油泵开始工作，将油槽内的高温油抽入不锈钢板式换热器，此时冷却循环水自动接通，通过板式换热器的多层不锈钢板槽进行换热，使经过冷却的淬火油再返回淬火油槽，如此往复循环，达到油槽降温目的。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。