双蒸发温度压缩机在家用新风空调系统中的应用

提出一款具有双缸、双吸气及双储液器结构的滚动转子式压缩机,该压缩机的2个汽缸独立吸气,独立控制2个蒸发温度,可应用于独立控制2个蒸发温度的家用新风空调系统。采用双蒸发温度压缩机的新风空调系统与采用传统压缩机的新风空调系统相比,理论COP高约23%,测试COP高约6.6%。

活塞式氢气压缩机排气温度超限故障诊断方法

针对活塞式氢气压缩机各级排气温度超限的故障难以用传统故障的二态性准确描述,以及目前未见能对该故障实施自诊断的故障诊断系统等问题,以DW-(5.6-13)/(0.2-0.5)-20型无油润滑变频活塞式氢气压缩机为研究对象,对相关零部件进行了重要度分析,并设计了故障自诊断系统。首先,对该故障搭建了模糊高木-关野(T-S)故障树模型,并利用基于贝叶斯网络(BN)的T-S故障树分析法对底事件进行了重要度分析,以确定薄弱环节和故障零部件诊断顺序;然后,利用模糊数表征了零部件的故障状态,对排气温度超限故障发生概率进行了预测;最后,设计了基于规则的故障诊断专家系统,并对实例进行了故障原因的推理排查。研究结果表明:基于规则的故障诊断专家系统在对现有故障数据进行分析后,其诊断结果与事实相符,说明该系统能够准确地诊断出故障原因,并进行自诊断;同时,基于BN的T-S故障树分析法,使该系统可对顶事件故障发生概率进行预测,为活塞式氢气压缩机故障诊断提供了一个可行方案。

E150柴油机缸内压缩温度场的全息干涉测量

介绍了采用激光双曝光全息干涉技术测取柴油机压缩温度场的基本原理及实验过程。提出了利用绝热压缩区的温度作为计算干涉条纹的初始条件，从而为计算全息干涉条纹所对应温度提供了可行的方法。由柴油机压缩过程中缸内的温度场的测试结果可以看出，在柴油机压缩过程中，缸内温度变化幅度在４０Ｋ左右，最大温度梯度是在靠近燃烧室壁面大约０．５ｍ ｍ 的区域内。本文的实验结果，为分析柴油机压缩过程缸内传热过程提供了依据：所使用的试验方法。

煤层气压缩机压缩温度对机组性能影响研究

为了探究影响煤层气压缩机工作性能的因素及规律,通过分析压缩机组效率的影响因素,确定了影响压缩机性能的指标为压缩气体多变指数、机组压缩端指示功率和机组系统级效率。现场测试结果表明:各级压缩进排气温度是决定机组工作状态及性能的重要因素;在煤层气站场压缩机结构参数、工况参数一定的情况下,压缩机组工作性能随压缩机进排气温度变化而变化;改变压缩温度可引起多变指数变化,从而可改变机组运行状态、指示功率及效率,在不改变工况参数情况下可根据冷却系统调节机组工作性能;机组一级压缩指示功率低于二级压缩指示功率,但一级压缩指示效率高于二级压缩指示效率,可以通过调整二级压缩工况来提升压缩机的工作性能。研究结果可为压缩机机组运行效率的提高提供指导。

基于主元分析法的多联机系统压缩机排气温度传感器故障检测与诊断

传感器是空调系统的重要组成部分,它对空调系统的运行状态进行实时监控,并将运行数据传输到控制系统中。传感器发生故障将使得空调系统偏离正常运行状态,导致系统能耗增加。主元分析法(Principal Component Analysis,PCA)是传感器故障检测与诊断中常用的数据分析方法。本文采集了多联机系统传感器正常运行数据,通过人为调整得到故障运行数据;采用正常运行数据对PCA进行建模,用训练好的模型对故障运行数据进行检测与诊断,分析检测与诊断结果。本文中传感器故障工况包含压缩机排气感温包漂移、脱落、精度下降以及完全失效故障。检测与诊断的结果为:基于PCA的多联机系统压缩机排气温度传感器故障检测与诊断结果良好。

地铁空调压缩机外露式排气温度保护开关故障及改造

压缩机排气温度开关保护是用来避免出现压缩机过热导致压缩机损坏。在制冷系统回气温度过高、压缩比过高、缺少压缩机冷冻油、冷凝压力过高等都会导致压缩机排气温度过高影响空调制冷系统正常工作。

块体非晶合金压缩变形研究进展

在约化压缩变形温度t=Tg／Tg为77K／Tg≤tr〈trel、tr≤tr〈trc2和trc2≤tr〈Tx／Tg时，一般块体非晶合金的压缩变形行为分别对应不均匀脆性断裂、非牛顿流变和牛顿流变；当应变速率约为10S时，临界约化压缩变形温度trcl在0．839～0．920之间，trc2=1．011；随着应变速率的降低，块体非晶合金由不均匀的脆性断裂转变为非牛顿流变的frcl、由非牛顿流变转变为牛顿流变的trc2均降低。低tr压缩变形试样表面的剪切带特征明显，但高t，压编变形由于均匀变形和热影响作用使剪切带不明显，且块体非晶合金的塑性随剪切带数量的增加而提高；随着tr的升高，块体非晶合金的断口显微组织演化过程分别为复杂不均匀的脉状纹络、较均匀的脉状纹络、熔滴状和岩浆流状组织。另外在极低约化压缩温度tr下Ni60Pd20P17B3和Ti40Zr25Ni3Cu12Be20块体非晶合金表现出非牛顿流变行为。非晶在一定温度的压缩变形会导致部分或所有非晶纳米晶化。

喷液在螺杆压缩机中的作用及影响

通过向螺杆压缩机内喷液可提高螺杆压缩机在工艺气处理方面的应用范围和效率。探讨了喷液的重要作用及对压缩机级性能的影响。

Effect of deformation temperature on microstructure and mechanical properties of 7055 aluminum alloy after heat treatment

The multi-pass hot compression test of 7055 aluminum alloy was performed at different temperatures and then the samples were heat treated by T6 heat treatment.The compressed samples were analyzed by OM and TEM.The results reveal that the average aspect ratio of the grains in the specimens compressed first decreases and then increases,the dislocation density decreases and subgrain diameter increases with the increase of deformation temperature.The effects of deformation temperature on the microstructure and mechanical properties of 7055 aluminum alloy after heat treatment were investigated by means of OM and mechanical property test.The results indicate that the deformation temperature significantly influences microstructure and mechanical property of 7055 aluminum alloy.The volume fraction of recrystallization grains presents a ＂fall-rise＂ pattern with the deformation temperature rising.The mechanical properties get better when the volume fraction of recrystallization grains decreases.Moreover,the volume fraction of recrystallization grain has a minimum value,appropriately 45%,and the sample exhibits the highest strength and elongation at the deformation temperature of 400 ℃.

两级冷凝热泵热水系统的实验研究

空气源热泵热水器运行在高温工作区时,压缩机功率及压缩机排气温度往往偏高,这不仅给机组的安全稳定性带来了隐患,同时系统的效率也会明显下降。针对这一问题,文中提出了一种两级冷凝热泵热水系统以及相应的控制方式,并进行了实验。实验结果表明,与传统的热泵热水器相比,这一系统不仅能提高供水温度,而且能让热泵热水机组在高温工作区的冷凝温度相对较低,从而在提高供水温度的同时,有效的降低了机组最高压缩机功率以及最高压缩机排气温度,系统运行安全、可靠、高效。

新型部分自复叠热泵的理论研究

提出了一种新型部分自复叠热泵,通过调节复叠率,该热泵可以控制压缩机的排气温度在安全温度(120℃)以内,并且把水加热到生活用热水所要求的温度(55℃),同时使热泵达到最高的能效比(COP).采用Matlab调用NIST制冷剂物性数据库Refprop 7.1编程对该热泵进行理论计算,分析了压缩机排气温度和热泵COP的影响因素,确定了最佳运行状态.理论计算结果表明:采用该新型部分自复叠热泵,可使压缩机排气温度下降30℃左右,当工质R22质量分数为0.28、冷凝器出口温度为55℃时,调节复叠率为0.717,可使压缩机排气温度降低至120℃,系统COP达到2.214.

压缩变形温度对车用贝氏体钢动力学及组织演变的影响

利用热模拟实验机研究不同压缩变形温度下车用贝氏体钢的相变规律,并分析其相变动力学及组织演变。研究结果表明:经过中、低温变形处理的试样曲线表现为抛物线上升。经过300与500℃变形处理后,贝氏体的相变速率增大,形成了更多铁素体;在700与850℃下,试样中贝氏体含有的铁素体比例比未进行变形处理的试样更低。经过变形处理的试样中贝氏体的形核位置包括晶内的剪切带(SB)、奥氏体晶界(AGB)、贝氏体板条晶棱(GE);经回复处理后,晶内剪切带的缺陷数量也明显减少,降低了晶内贝氏体板条含量;经过低温变形处理可以使晶内的剪切带数量增加。试样进行等温处理生成了板条状贝氏体组织。经过低温变形的试样生成短粗状的贝氏体板条,当随变形温度升高后,铁素体板条的厚度不断减小。

采用激光双曝光全息干涉技术研究相互耦合的柴油机压缩温度场与喷雾场

为探讨柴油机缸内压缩温度场对柴油机喷雾过程的影响 ,采用激光双曝光全息干涉应用于柴油机缸内喷雾与压缩温度场的耦合过程。得到了温度场与浓度场耦合的全息干涉条纹 ,直观地显示了喷雾油束与温度场的形状。

柴油机低温起动的影响因素及其改善

柴油机起动性能的好坏,对其易操作性、工作可靠性、使用耐久性和经济性等均具有很大影响,特别是对带动螺旋桨的船舶主柴油机影响更甚。由于船舶航行区域的不同,季节和海况的变化。无论是柴油机主机还是副机均要求其具有良好的起动性能。

Modeling on dynamic recrystallization of aluminium alloy 7050 during hot compression based on cellular automaton

The dynamic recrystallization(DRX) process of hot compressed aluminium alloy 7050 was predicted using cellular automaton(CA) combined with topology deformation. The hot deformatation characteristics of aluminium alloy 7050 were investigated by hot uniaxial compression tests in order to obtain the material parameters used in the CA model. The influences of process parameters(strain, strain rate and temperature) on the fraction of DRX and the average recrystallization grain(R-grain) size were investigated and discussed. It is found that larger stain, higher temperature and lower strain rate(less than 0.1 s^(–1)) are beneficial to the increasing fraction of DRX. And the deformation temperature affects the mean R-grain size much more greatly than other parameters. It is also noted that there is a critical strain for the occurrence of DRX which is related to strain rate and temperature. In addition, it is shown that the CA model with topology deformation is able to simulate the microstructural evolution and the flow behavior of aluminium alloy 7050 material under various deformation conditions.

Primary and secondary consolidation compression for saturated soil considering coupling effect of loading and heating

Geotechnical engineering that relates to the energy and environmental problem is receiving more and more attention worldwide.It is of great theoretical and practical value to study the properties of soil under thermal mechanical coupling and its mathematical description.Firstly,based on the general function,a unified primary and secondary consolidation model of saturated soil considering heating temperature is deduced.Combining the existing research achievements,a practical model is obtained which comprehensively reflects the effective stress change,creep and heating effects.After that,a series of thermo-consolidation tests are carried out using a temperature controlled consolidation instrument to study the effects of effective stress,temperature and consolidation duration on saturated soils.The corresponding functional formulas and parameters are obtained thusly.On this basis,the calculation and analysis are carried out to check the reliability and applicability of the newly proposed model.The new model is simple and practical and the parameters are easy to be obtained.And it describes the main law of consolidation compression of saturated soils under the thermal mechanical coupling effect.Therefore,it is suggested for theoretical analysis of thermal geotechnical engineering problems.

Ultrasonic Studies of 4-Aminobutyric Acid in Aqueous Salbutamol Sulphate Solutions at Different Temperatures

Ultrasonic speeds of 4-aminobutyric acid in 0.0041,0.0125 and 0.0207 mol·kg^-1 aqueous salbutamol sulphate（SBS） solutions are measured at 308.15,313.15 and 318.15 K.Isentropic compressibility kS,change in isentropic compressibility△k S,relative change in isentropic compressibility（ △kS /kS^0） ,apparent molal compressibility kφ,limiting apparent molal compressibility kφ^0 ,transfer limiting apparent molal compressibility k φ^0,hydration number nH,pair and triplet interaction parameters kAS,kASS are estimated.The above parameters are used to interpret the solute-solute and solute-solvent interactions of 4-aminobutyric acid in the aqueous salbutamol sulphate solutions.

Transformation mechanism and mechanical properties of commercially pure titanium

In order to establish the rolling process parameters of grade-2 commercially pure titanium （CP-Ti）, it is necessary to understand the transformation mechanism and mechanical properties of this material. The β→α transformation kinetics of the grade-2 CP-Ti during continuous cooling was measured and its hot compression behavior was investigated using Gleeble-1500 thermal mechanical simulator. Dynamic CCT diagram confirms that cooling rate has an obvious effect on the start and finishing transformation and microstructures at room temperature. The critical cooling rate for γ-phase transforms to a phase is about 15℃/s. When the cooling rate is higher than 15 ℃/s, some β phases with fine granular shape remain residually into plate-like structure. The plate-like a phase forms at cooling rate lower than 2 ℃/s, serrate a phase forms at medium cooling rates, about 5-15℃/s. The flow stress behavior of grade-2 CP-Ti was investigated in a temperature range of 700-900℃ and strain rate of 3.6-40 mm/min. The results show that dynamic recrystallization, dynamic recovery and work-hardening obviously occur during hot deformation. Constitutive equation of grade-2 CP-Ti was established by analyzing the relationship of the deformation temperature, strain rate, deformation degree and deformation resistance.

RELATIONSHIP BETWEEN P-T CONTITIONS OF TWO PHASES OF TAN-LU STRIKE-SLIP SHEAR ZONES AND DELAMINATION OF OROGENIC BELTS ON THE EASTERN MARGIN OF THE DABIE MOUNTAINS

The Tan-Lu fault zone joins the Dabie Mountains on its eastern margin, and offsets the Dabie and Sulu orogenic belts sinistrally for about 500 kin. On the basis of calculation of temperature and pressure experienced by the two phases of the fault zone as well as the thermo-chronological information on mylonite from the earlier and later Tan-Lu fault zones on the eastern margin of the Dabie Mountains, this paper discusses the delamination history and uplifting magnitudes of the Dabie Mountains from earlier Jurassic to earlier Cretaceous. From mineral assemblages, mineral deformation and muscovite-chlorite geothermometry calculation, it is known that the temperature experienced by the two phases of Tan-Lu fault zones are between 40℃ and 450℃, and the confining pressures are between 0.25Gpa and 0.36GPa for the earlier shear zones and 0.24-0.39GPa for the late shear zones. According to the geobarometry of Si-in-phengite and by considering shear heating and tectonic over-pressure, it is concluded that the maximum formation depths for the two phases of the ductile shear zones are not more than 12 kin. Differential formation depths for the two phases of shear zones are 1-2 km at most. At about 190 Ma and 128 Ma, the Tan-Lu fault zone experienced two phases of cooling events. During this period, the eastem margin of the Dabie Mountains experienced a tectonic calm period and no uplifting. According to information from the Tan-Lu fault zone, the uplifting magnitudes of the Dabie orogenic belts are not more than 12 km during the earlier Cretaceous.

Effects of strain rate and temperature on microstructure and texture for AZ31 during uniaxial compression

In order to investigate the effects of strain rate and temperature on the microstructure and texture evolution during warm deformation of wrought Mg alloy,AZ31 extruded rods were cut into cylinder samples with the dimension of d8 mm×12 mm.The samples were compressed using a Gleeble 1500D thermo-mechanical simulation machine at various strain rates(0.001,0.01,0.1,1 and 5 s- 1)and various temperatures(300,350,400 and 450℃).The microstructure and texture of the compressed samples at the same strain under different deformation conditions were studied and compared by electron backscatter diffraction(EBSD)in scanning electron microscope(SEM).The results show that the size of recrystallized grains in the deformed samples generally increases with the decrease of strain rate and the increase of temperature.After 50%reduction,most basal planes are aligned perpendicular to the compression direction at relatively high strain rate(>0.01 s- 1)or low temperature(<350℃).The optimized strain rate is 0.1 s- 1for uniaxial compression at 300℃,which produces about 80%of small grains(<5μm).