一款小角X射线散射原位测量专用简易样品加热装置

原位加热实验是同步辐射小角X射线散射领域的新热点。本文针对同步辐射小角X射线散射中需要加热并原位实时检测的实验而设计的一款样品简易原位加热专用装置,该装置主要由温控器、样品池、固定架组成,它具有结构简单、操作容易的特点。本文介绍该装置的基本结构、特点并采用该装置进行原位加热干燥褐煤实验,通过分析实验结果验证装置的可行性。     

一种用于热敏电阻温度系数测量加热器的制作

本文介绍一种加热装置的制作，该装置可代替热敏电阻温度系数测量实验中的加热油槽或水槽。     

一种微波加热装置的风冷散热研究

微波加热装置工作过程会散发大量的热量,如果不能及时排出,会造成输出功率的下降。本文以九个磁控管加热单元组成的微波加热装置为研究对象,首先提出一种风冷散热结构设计,接着通过Fluent热仿真软件验证结构设计的合理性,然后通过对比分析加热装置进风口位置、面积大小等因素对散热效果的影响,对散热结构进行改进,进一步提高了内部磁通管结构的温度一致性,强化了加热装置的散热能力。     

基于IGBT的刀柄热装装置的设计与实现

热装刀柄及其工具系统是高速加工工具系统的主要形式之一,由于其具有高精度、强夹持力、高平衡性等特点,在高速切削加工中得到了广泛应用。刀柄热装装置就是运用电磁感应加热原理,利用刀柄材料的热胀冷缩,对刀柄进行加热进而完成刀具的取出和放入。针对国内刀柄热装装置的空白,设计了一种基于IGBT的刀柄热装装置。该装置以IGBT为核心,设计了IGBT全桥逆变电路以及以IR2110为驱动芯片的驱动保护电路,研发了基于Maxwell电磁场分析的感应加热线圈,并给出了刀柄热装装置的整体框架以及具体实施方式,完成了整个装置的研制,最后实验验证了该装置可实现刀柄热装装置的功能,并经过大量后期优化实验建立了对应于不同口径刀柄的最优加热时间和最优加热频率的数据库。     

电感贮能的“开关-阻容”换流线路

本文研究了采用电感贮能作为环流-Ⅰ装置的欧姆加热电源。提出了“开关-容阻”换流线路,并对“开关-容阻”换流线路进行了分析。最后,结合环流-Ⅰ装置的欧姆加热要求进行了供电系统的方案计算。     

托卡马克放电过程中偏滤器位形的演化

本文研制了适用偏滤器位形的１－１／２维托卡马克输运程度，并该程序模拟了托卡马克装置放电期间偏滤器位形的演化。在纯欧姆加热和有辅助加热两种放电方式下，对不同等离子体电流分布，拉长比，三角形变等参数下等离子体平衡位形的演化过程进行了计算机模拟。     

硼酸浓度及热面倾角对沸腾换热影响的实验研究

基于搭建的加热面倾斜可调式沸腾传热实验装置,通过对比蒸馏水沸腾换热实验与实验关联式,在验证实验装置及测量方法可靠性的基础上,对不同浓度硼酸溶液在不同加热面倾斜角下的沸腾换热特性进行了实验研究和比较,获得了硼酸浓度和加热面倾斜角变化时的平均换热系数。实验结果表明,对于浓度为1.3~9.5 g/kg的硼酸溶液,换热系数随着浓度的增加而增大,但是达到5 5 g/kg后趋于平缓;相同浓度时不同倾斜角下平均换热系数最大相差8%。     

HL-2A装置二级加热工作进展

本年度等离子体加热研究室开展了以HL-2A装置二级加热为主要任务的科研项目，完成了电子回旋共振加热项目的工程研制（2MW／1s），进一步完善了低杂波电流驱动项目，在HL-2A装置实验中取得了良好的结果，目前正在开展中性求项同的建设。各项研究工作将在本文中作一介绍。     

低进汽压力下超音速两相流升压特性实验研究

本文采用实验方法研究了进汽压力为0.2 MPa以下时,由蒸汽喷嘴、混合腔及相应的阀门和管道组成超音速汽液两相流升压加热装置的运行特性。实验表明在进汽压力为0.1 MPa-0.2 MPa时,超音速汽液两相流升压加热装置都可稳定可靠地运行,且升压效果明显,可满足电力、供暖、轻工等许多行业蒸汽加热的要求。     

二级6-8型静高压装置厘米级腔体内置加热元件的设计与温度标定

最近研制的二级6-8型大腔体静高压装置可在15GPa以上的压力条件下进行厘米级样品的高压合成,对此装置的高压腔内置加热元件进行了设计与实验测试,并标定了不同的腔体压力下加热功率和温度的关系,同时用六角氮化硼在没有触媒的情况下转化成立方氮化硼的合成实验验证了此装置所达到的温压条件。实验结果表明,所设计的加热组装在高压高温下运行稳定,可以在压力超过14GPa、温度超过1 800℃的条件下进行厘米级样品的高温高压处理。     

Collisionless electron heating by capacitive rf sheaths

High-frequency plasma discharges are often sustained by collisionless heating of electrons; the nature of these mechanisms is a central problem in the theory of such discharges. In capacitive discharges, collisionless heating occurs near boundaries, and is usually attributed to inelastic collisions of electrons with oscillating plasma sheaths, regarded as moving rigid barriers. We show that, when current conservation is required, such heating necessarily vanishes, and we conclude that this model of the heating process is not correct. We develop an alternative view that associates the heating with acoustic disturbances in the electron fluid. An analytic model, based on moments of the Vlasov equation, gives results in good agreement with particle-in-cell simulations. In terms of individual particle dynamics, this acoustic heating may be interpreted as a transit-time effect.     

Analysis of directional radiative behavior and heating efficiency for a gas-fired radiant burner

For the purpose of energy conservation and uniform heating of object surface, a gas-fired porous radiant burner with a bundle of reflecting tubes is developed. A physical model is developed to simulate the directional radiative behavior of this heating device, in which the Monte Carlo method based on the concept of radiation distribution factor is used to compute the directional radiative behavior. The effects of relating parameters on the directional behavior of radiative heating and the heating efficiency are analyzed. With the increase of the length-to-radius ratio of tube, the radiation heating efficiency decreases, but the radiation energy incident on the object surface is more collimated. The radiation heating efficiency increases with the specular reflectivity. With the increase in length of tube segment with specular reflective surface, the radiation heating efficiency increases, but the extent of concentration and collimation of radiative energy decreases. For real design of the heating device, some trade-offs are needed to balance the radiation heating efficiency and the uniformity of radiative heating of object surface.     

Effect of magnetic field decay on the chemical heating of cooling neutron stars

The effect of magnetic field decay on the chemical heating and thermal evolution of neutron stars is discussed in this paper. Our main goal is to study how the chemical heating mechanism and thermal evolution are changed by the field decay and how the magnetic field decay is modified by the thermal evolution. We compare stars cooling with chemical heating with one without chemical heating and find that the decay of the magnetic field is delayed significantly by the chemical heating. We find that the effect of chemical heating has been suppressed through the decaying magnetic field by the spin-down of the stars at a later stage. Compared with typical chemical heating, we find the decay of the magnetic field can even cause the surface temperature to turn down at an older age. When we discuss the cooling of neutron stars, we should consider the coupling effect of the magnetic field and the rotational evolution of neutron stars on the heating mechanisms.     

加热对自然转捩湍斑产生影响的实验研究

本文利用流动显示和高速摄像技术，在湍流度为1％的水洞中，对加热的细长旅成体鱼雷模型表面的流动转捩过程进行了实验研究。实验发现，加热对自然转捩过程中湍流斑的猝发有明显影响，加热减小了湍斑产生的频率，增加了湍斑间的展向间距，使转捩过程中层流转变为完全湍流的过渡区延长．加热对瑞斑产生的纵向位置无明显影响。本文的实验结果正好解释在较高湍流庭环境中的加热减阻机理．     

Simulation of heat transfer processes in an unconventional furnace

Heat transfer simulation is of great significance for the heating equipments control. In this paper, a set of models is proposed to solve heat transfer problems in a furnace, including radiation and convection. The heat transfer models are integrated with a furnace model to simulate the heating process. The heating rate is increased due to enhanced heat transfer at the surfaces by changing furnace chamber geometry. A fixed grid enthalpy formulation is applied to model heat transfer for an oval geometry. The heating temperature was found to increase linearly with curvature of the interior.     

相变材料蓄能式低温热水采暖地板热性能模拟

提出了一种采用定形相变材料蓄能的低温热水采暖地板形式。为了研究定形相变材料蓄能式低温热水采暖地板的传热性能,建立了该地板的传热分析模型。分析了相变材料的相变温度对地板表面平均热流密度和蓄能比的影响;比较了相变材料潜热蓄能地板与混凝土显热蓄能地板的热性能差异。结果表明:定形相变材料地板停止加热后仍可以在较长时间内保持稳定的热流密度。同时定形相变材料地板具有较大的蓄能比,使其夜间蓄存的热量可被更多地用于日间供热。     

Localized rapid heating process for precision chalcogenide glass molding

Precision glass molding is an important process for high volume optical fabrication. However, conventional glass molding is a bulk heating process that usually requires a long thermal cycle, where molding assembly and other mechanical parts are heated and cooled together. This often causes low efficiency and other heating and cooling related problems, such as large thermal expansion in both the molds and molded optics. To cope with this issue, we developed a localized rapid heating process to effectively heat only very small part of the glass. This localized rapid heating study utilized a fused silica wafer coated with a thin graphene layer to heat only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating heat on and near the coating. The feasibility of this process was validated by both experiments and numerical simulation. To demonstrate the advantages of the localized rapid heating, both localized rapid heating process and bulk heating process were performed and carefully compared. The uniformity and quality of the molded sample by localized rapid heating process was also demonstrated. In summary, localized rapid heating process by using graphene coated fused silica wafer was characterized and can be readily implemented in replication of micro scale chalcogenide glasses.     

Analytical solution for multilayer assembly including heating and cooling cycles with laser pulse parameter variation

Laser heating of surfaces is involved with heating and cooling cycles. Material response to a laser pulse in the heating cycle is rapid while in the cooling cycle it is gradual. In this case, temperature rises rapidly in the heating cycle while temperature decay is gradual in the cooling cycle. Depending on the laser pulse properties (pulse length and intensity), the rise and fall of temperature profiles change in the surface region of the substrate material. In the present study, an analytical solution for laser heating pulse is presented and a closed-form solution for temperature distribution inside the multilayer assembly is obtained. Steel is considered as top layer while copper is situated below steel in the multilayer assembly. It is found that the analytical solution agrees well with the numerical predictions. Temperature rise in steel is higher than copper. This is due to the thickness of steel, which is larger than the absorption depth. In this case, internal energy gain dominates over the heat conduction in the energy transport process.     

自激振荡流热管脉冲加热强化传热实验研究

自激振荡流热管也称为脉动热管,是一种新型高效的传热元件。本文提出了采用脉冲加热代替常规连续热源加热强化自激振荡流热管传热的方法,并对其进行了实验研究。实验结果显示,脉冲加热时热管冷、热端壁面温度的振荡频率明显大于连续加热热管的壁面温度振荡频率。在相同的加热功率下,当脉冲宽度在200-1000 ms时,脉冲加热热管的传输热流量与当量导热系数均大于连续加热热管的传输功率和当量导热系数．这表明脉冲加热强化自激振荡流热管传热的方法是可行的．     

光折变全息CO2激光局域热固定

提出用ＣＯ２激光对记录于ＬｉＮｂＯ３晶体中的全息进行实时实时地局域热固定，通过脉冲加热和加载吸热体，可以使得温度范围在１００～２００℃之间的区域接近于加热光的形状，分布于一局部范围，文中给出了加热模型及其数值解，通过得到了最优解参数进行了一系列实验，实验结果显示，用ＣＯ２激光可以成功地光折变全息进行实时地地局域热固定，并且加热时间短，固定转换效率较高。