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基于吸收式制冰机,利用船舶柴油机尾气进行了尾气余热制冰实验。考察了制冰机对柴油机工作的影响及柴油机功率、环境温度等因素对制冰量的影响,得到大量实验结果,通过对实验结果进行分析,得出了柴油机尾气余热制冷特点及规律。 相似文献
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轮毂轴承是汽车底盘车轮上重要的零部件,为了降低汽车单位里程油耗或电耗,对在行车过程中环境温度对车轮轮毂轴承摩擦力矩和摩擦能耗的影响进行了研究。首先,给出了2种轮毂轴承摩擦力矩理论计算公式,提出了轮毂轴承摩擦能耗试验评估计算方法;然后,根据公式及相关原理对环境温度影响轮毂轴承摩擦能耗进行了理论分析,得出了初步结论;最后,利用目前国际最先进的轮毂轴承摩擦力矩及能耗试验设备,设置了特定路谱试验程序,按照恒定车速、中国路谱轻型汽车循环乘客试验(CLTC-P)和欧洲路谱新标欧洲循环测试(NEDC)试验条件,分别在不同的温度环境下进行了试验验证。研究结果表明:汽车在恒定车速下行驶,环境温度越高,轮毂轴承摩擦力矩越小,在40℃高温环境下,轮毂轴承摩擦力矩比-20℃低温下的摩擦力矩降低了约50%;汽车无论是按照CLTC-P路谱还是NEDC路谱行驶,环境温度越高,轮毂轴承摩擦能耗越小,在40℃高温环境下,轮毂轴承摩擦能耗比-20℃低温下的摩擦能耗降低了约60%,这也是汽车在冬天时单位里程油耗或电耗比夏天高的原因之一。 相似文献
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《流体机械》2017,(8)
工况的变化对空气源热泵系统的优化提出了更高要求,环境温度作为重要影响参数,需要通过大量试验找寻其对空气源热泵热水器的影响规律,从而做出相应的控制策略。本文模拟不同环境温度对空气源热泵热水器进行试验,结果表明:(1)随环境温度的降低过热度逐渐减小,系统的制热量受过热度影响,过热度越低制热量越大,当过热度为0℃时制热量开始逐渐下降;(2)环境温度越低,系统的压比越大、排气温度越高、过热度越小,压缩机更易湿压缩加剧耗功的增长,但能有效降低排气温度;(3)随着环境温度的降低,系统的平均能效比COPa是逐渐减小的,环境温度越低系统整体制热效果越差,加热运行的时间越长。 相似文献
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某空调系统运行参数的遗传算法优化 总被引:1,自引:0,他引:1
《流体机械》2016,(12):65-70
空调系统能耗占建筑能耗的50%以上,减少空调系统能耗可在一定程度上降低建筑能耗。以宁波市某办公建筑的空调系统为研究对象,对空调系统各设备建立基于功率的能耗模型,并用实数编码遗传算法对典型日空调系统的冷水供水温度、冷水流量和冷凝侧风量进行求解,得出了适合于该建筑的节能运行策略。研究结果表明,优化后空调系统全天总能耗为1578.86k W,比优化前该系统日平均能耗(1819.70k W)节能13.24%。 相似文献
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Sung Joo Hong William E. Lear Min Soo Kim 《Journal of Mechanical Science and Technology》2014,28(4):1581-1588
The power, water extraction, and refrigeration (PoWER) system generates electric power, potable water and refrigeration effects simultaneously, and is composed of a micro-turbine and vapor absorption refrigeration system, which typically uses ammonia, heat exchangers, and a turbocharger. In order to improve the efficiency and the electric output power of the micro-turbine portion of the PoWER system, attempts have previously been made to reduce the inlet temperature of the compressor. However, it was problematic to drive it below the freezing point since frost or ice forms from the humidity in re-circulated air. As a result, the ice accretion that attaches on the bell mouth or guide vane might increase the pressure drop, leading to performance loss. Furthermore, large sections that break from the ice accretion may cause damage to the compressor blades. In this paper experiments have been conducted under the same environmental conditions as the PoWER system in order to observe the physical characteristic of the frost formation on cylindrical tubes. The results show the thickness of the frost formation for different air velocities (3, 5, 7 m/s) and surface temperatures (?9.8, ?16.6, ?24.4°C) with respect to time. 相似文献
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建立水流外掠冰柱实验台,分别开展了水流速度(0.02、0.03、0.04、0.05、0.06和0.07m/s)、水流温度(7、10、13、16和19℃)、冰柱直径(60、70、80和105mm)及冰柱初始温度(-12、-8和-5℃)对于冰柱融化速率的影响研究。通过对融化时间的统计和分析,获得以下结论:水流温度对于融化时间的影响呈幂函数规律;水流速度和冰柱直径对于融化时间的影响呈线性规律;冰柱初始温度对于融化时间影响较小。 相似文献
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Mária Čarnogurská Miroslav Příhoda Marcel Koško René Pyszko 《Journal of Mechanical Science and Technology》2012,26(12):4161-4169
Results of verification of two mathematical models presenting the creation of three pollutants at wood combustion in a low power pellet boiler are published in this article. The type of boiler used in the experiment was EKO-KARBON ÚSPOR-AUTOMAT with nominal power of 18 kW. Nitrogen oxides, carbon oxide, and total organic carbon were tested. The models elaborated on the basic theory of dimensional analysis. In the first model, the emissions produced in the wood combustion process were described under the condition that the combustion product temperature in boiler outlet is one relevant parameter in the mathematical model. Combustion air volume flow, combustion air temperature, combustion product temperature, boiler power, and wood calorific power are other parameters in the model. The second model describes the mutual coherence of the same pollutants, provided that flame temperature, instead of combustion product temperature, is incorporated into the model. The outputs obtained from both models are subjected to the same combustion conditions. 相似文献
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随着非道路移动工程机械发动机机功率的不断增加,为满足柴油机的动力性和经济性指标,对增压空的气冷却提出了越来越高的设计要求。本文通过场地试验的方法对比研究了水冷中冷器与空冷中冷器对某款装载机柴油机工作特性的影响。试验结果表明,水冷中冷器相比于传统的风冷中冷器能更有效的降低柴油发动机的进气温度:水冷中冷器在铲装作业和高速跑工况下增压空气平均出温分别比空冷中冷器低27.6%和10.5%,柴油机扭矩提升为1.6%和6.3%,并且油耗降低了4.0%和2.5%。相对进气压力对柴油机经济性指标有一定影响,适当增加进气压力可以减少油耗。 相似文献
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首先对现有采暖空调系统的输送能耗状况及其存在的问题做了深入分析,采暖空调系统的输送系统可等效为异程或者同程式水力模型。然后分别对异程或者同程式水力模型的能量模型、温度模型及压力模型做了深入研究,发现采暖空调系统的设计模型是导致输送系统“大流量、小温差、高功耗”的根本原因。最后提出一种新型空调输送系统的解决方案——双冷源串联两管制空调系统,该系统通过提高输送系统设计供回水温差的方法解决输送系统“大流量、小温差、高功耗”,不仅有效地解决了输送系统“大流量、小温差、高功耗”的问题,而且提高了冷源的效率。 相似文献
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废气涡轮增压中冷柴油机广泛应用于海上油气开发,在柴油机运行过程中,增压后空气温度下降可以提高进气空气密度,进而提高柴油机功率以及效率。通过现场运行分析发现,随着柴油机功率提高和空冷器换热效率下降,增压空气温度上升,而柴油机低温水出口温度设定为50℃不变,导致了柴油机性能降低。本研究通过理论分析、实验等方式对该柴油机进气温度可变性进行分析研究,寻求最佳进气温度以提高主机燃油效率、降低排气温度及污染物排放。 相似文献
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The effects on water of two cooling methods, immersion in a liquid cryogen and high-pressure freezing, were studied by X-ray cryodiffraction on different sucrose solutions. The nature of the ice formed by each method depends on both the sucrose concentration and the specimen thickness. In order to compare the two methods, we mainly studied specimens having a thickness of 0.2 mm. Under these conditions, freezing by immersion gives rise to hexagonal (IH), cubic (IC) and amorphous (IV) ices when the sucrose concentration (weight/weight) has a value within the range 0–30%, 30–60%, 60% and higher, respectively. The temperature of the phase transitions IV–IC, IC–IH depends on the sucrose concentration. High-pressure freezing gives rise to two specific forms of ice: an amorphous and a crystalline ice (ice III). Ice III is observed when pure water samples are high-pressure frozen provided that the sample temperature does not rise above −150 °C. Above this temperature, ice III transforms into hexagonal ice. Amorphous ice is formed when the sucrose concentration is higher than 20%. The amorphous ice formed under high pressure has a similar, but not identical, X-ray diffraction pattern to that of amorphous ice formed at atmospheric pressure. While the X-ray diffraction pattern of amorphous ice formed at atmospheric pressure (IV) shows a broad ring at a position corresponding to 0.37 nm, that of high-pressure amorphous ice (IVHP) shows a broader ring, located at 0.35 nm. IVHP presents a phase transition (IVHP–IV) at temperatures that depend on the sucrose concentration. We also observed that some precautions have to be taken in order to minimize the alcohol contamination of high-pressure frozen samples. The ice-phase diagram presented in this paper should be taken into account in all methods dedicated to the structural study of frozen biological specimens. 相似文献