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三角形长喉道量水槽是一种明渠量水设施。目前的流量计算主要是经验公式,经验公式的应用受试验条件的限制较大。本文根据边界层位移厚度和临界水深理论,推导了该量水槽流量的理论设计方法,该方法可以根据渠道的比降、糙率和设计流量灵活的调整量水槽的几何尺寸,喉道底部也可以根据量水范围的要求设计成平底或底部拱起。用文献[1]的实验结果进行了比较,计算与实测值一致。在此基础上,还提出了三种复合三角形断面长喉道量水槽的理论计算方法。 相似文献
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当环境温度变化或燃气轮机进气加热时,燃气轮机逻辑中沃伯指数公式计算值保持不变,不能实时 反映燃气轮机的燃烧工况。通过分析燃气轮机DLN2.0 +燃烧系统的天然气校正沃伯指数公式,提出压气机 进气温度对校正沃伯指数更合理的修改公式。此新公式能全面正确反映环境温度变化或进气加热时的沃伯 指数变化,对现场实际运行和燃气轮机系统优化设计也有帮助。 相似文献
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针对三个泉倒虹吸过流量富余的问题,基于工程特点及其水力设计方法,借鉴大口径钢管和预应力钢筒混凝土管(PCCP管)当量粗糙度的取值,根据雷诺数与相对粗糙度,结合莫迪图判别分析了大流量工况下倒虹吸管道水流流态,在此基础上,利用齐恩公式、海曾—威廉公式、谢才公式分别计算了三个泉倒虹吸水头损失值,并与实测资料进行对比分析。结果表明,随着管径增大,管壁光滑程度增加,使得PCCP管内水流处于紊流过渡区而非阻力平方区,因此不应选用谢才公式,而这正是导致三个泉倒虹吸过流能力与设计标准不符的主要原因。此外,发现齐恩公式、海曾—威廉公式适用于大口径有压PCCP管沿程水头损失计算。 相似文献
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喷油嘴喷孔角度坐标变换分析 总被引:1,自引:0,他引:1
利用空间直角坐标系变换方法 ,推导出喷油嘴喷孔角度设计图样和加工图样标注形式之间相互转换的一般公式 ,提出一种由设计角度公差制定加工角度公差的方法 ,用全微分法导出加工公差的近似求解公式 ,对各种公式分别进行了验证和应用举例 ,绝大多数喷孔加工角度公差范围应在原设计角度公差范围基础上有所缩小 ,方能保证设计角度公差要求。 相似文献
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对CA6102汽油机进行的强化快速加灰试验表明,发动机的磨损与空气滤清器的效率有很大的关系。通过严密的理论推导,得出了不同粉尘浓度条件下发动机的磨损与空气滤清器滤清效率的经验公式。根据此经验公式,不仅定性且可定量地从空气滤清器的角度来分析研究发动机的磨损,同时给出了典型路面条件下空气滤清效率的合理限值。此经验公式对研究发动机的磨损、设计及评价发动机空气滤清器,有一定的指导意义。 相似文献
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提出了一种质量比能量型锂离子电池型号设计思路,推导出了以正极片数量和正极片长宽比为自变量的电池质量公式,并对公式的正确性和准确性进行了验证,通过实例阐述了电池质量公式的应用方法和实际意义。研究结果表明,电池质量公式在定义域内存在最小值点,可以通过求解电池质量公式的最小值为高质量比能量电池型号设计提供理论依据。 相似文献
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《节能》2021,(2)
选择性催化还原(SCR)是目前主流的烟气脱硝技术,在SCR脱硝系统设计中,催化剂体积准确设计是事关脱硝效率和成本支出的重要环节。传统的SCR催化剂体积设计主要采用经验公式计算,但由于SCR催化剂体积设计的影响因素众多,使得经验公式不仅复杂且适用性较窄。基于此提出基于样本优化的BP神经网络催化剂体积设计预测方法。研究结果表明,针对已构建的BP神经网络模型,通过平均影响值算法(MIV)对原始样本进行输入参数筛选和优化,降低了神经网络复杂性,提高了模型精度,平均预测误差从15.46%下降至10.32%。进一步通过BP神经网络预测筛选辨识样本中的不良数据,基于剔除了不良样本训练的BP神经网络,平均预测误差可进一步下降至2.55%,这一方法可为催化剂体积设计提供参考和指导。 相似文献
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ASME法规规定了锅炉和压力容器产品受压元件的设计、制造、检验方面的要求。舳法规中关于水压试验的有关规定,需要企业在具体检验中细化。在水压试验和气压试验中,目视检验是经常使用的检验方法,在产品生产过程的检查中,目视检验同样是重要的检验方法。 相似文献
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《International Journal of Hydrogen Energy》2022,47(49):21273-21286
The rotational speed and load are two main factors affecting the tribological properties of the hydrostatic thrust bearing, especially under high-speed and heavy-load conditions. The three-dimensional simulation models of oil film and bearing friction pairs are established. The oil film pressure field, oil film temperature field, bearing friction pairs deformation field, and oil film thickness field are obtained and discussed under high-speed and heavy-load working conditions. A test rig for studying high-speed and heavy-load tribological properties of hydrostatic thrust bearing with double rectangular recess is developed. The feasibility of the simulation method is validated by experiments. It is found that a reasonable matching relationship between rotational speed and load is obtained, and the burden is the main factor affecting oil film pressure. Still, the rotational speed has a significant impact on the oil film temperature. The influence of friction pairs deformation on tribological properties under high-speed and heavy-load working conditions is explored, the oil film thickness is obtained, and dry friction will appear if the working conditions are further enlarged. This work guides the application of hydrostatic thrust bearing under working conditions of high speed and heavy load. 相似文献
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Dongliang Wang Binbin Liao Chunyong Hao Ange Wen Jinyang Zheng Peng Jiang Chaohua Gu Ping Xu Qianghua Huang 《International Journal of Hydrogen Energy》2021,46(23):12605-12614
Currently, the periodic inspection of composite tanks is typically achieved via hydrostatic test combined with internal and external visual inspections. Acoustic emission (AE) technology demonstrates a promising nondestructive testing method for damage mode identification and damage assessment. This study focuses on AE signals characteristics and evolution behaviors for used 70 MPa Type IV hydrogen storage tanks during hydrostatic burst tests. AE-based tensile tests for epoxy resin specimen and carbon fiber tow were implemented to obtain characteristics of matrix cracking and fiber breakage. Then, broad-band AE sensors were used to capture AE signals during multi-step loading tests and hydrostatic burst tests. K-means ++ algorithm and wavelet packet transform are performed to cluster AE signals and verify the validity. Combining with tensile tests, three clusters are manifested via matrix cracking, fiber/matrix debonding and fiber breakage according to amplitude, duration, counts and absolute energy. The number of three clustering signals increases with the increase of pressure, showing accumulated and aggravated damage. The sudden appearance of a large number of fiber breakage signals during hydrostatic burst tests suggests that the composite tank structure is becoming mechanically unstable, namely the impending burst failure of the tank. 相似文献
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利用MDT进行气缸盖冷却水腔设计 总被引:2,自引:0,他引:2
赵臣 《柴油机设计与制造》2001,(3):41-44
在内燃机的制造过程中,气缸盖作为内燃机的重要组成部分必须引起足够的重视。由于气缸盖的热负荷较大,它的合理冷却是发动机正常运行的有力保障。气缸盖的冷却由冷却水腔来完成,只有合理设计冷却水腔的结构,才能达到内燃机的设计性能指标。本设计基于美国AutoDESK公司的MDT和AutoCAD软件开发平台,利用二次开发技术进行设计,使用现代流行的曲面和实体造型方法,能够满足产品的基本需要。通过使用特征参数化造型方法,使其按照用户要求能够自动建立三维几何模型。 相似文献
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Renewable energies (solar and wind energies) associated to reverse osmosis (RO) are gaining renewed interest for brackish and seawater desalination. Another potential source of energy is the hydrostatic pressure at a sufficient operative depth or height to perform the RO process. This article provides a comparison of the energy requirement of various hydrostatic pressure-RO plants. For submarine and underground plants, the required energy is equal to 2.98 and 3.54 kWh, respectively, for 1 m3 of produced fresh water. In case of hydrostatic pressure generated by a column of water due to a head difference between the sea level and an adjacent mountain, the energy required is equal to 1.4 kWh. These energy requirements compare well with the usual energy requirement for desalination, between 3 and 10 kWh for 1 m3 of produced fresh water. However, the main drawback associated with hydrostatic pressure plants relates to their construction and their maintenance, which are expected to be more complicated and costly than for a ground plant. 相似文献
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为了全面了解发动机冷却性能,本文研制了一套冷却水套内水路分布测试系统,实验装置为设计性能优良的冷却系统、为建立设计系统数据库,以及为确定评价设计系统优劣的指标和提供实验研究的手段,研究设计了一套缸盖上水孔流量测量系统,为缸盖内流场分布的数值模拟提供更准确的边界条件并可对各缸流量分布的合理性进行评价。 相似文献
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The air gap between absorber and cover glazing in fiat plate collectors has been optimized experimentally by designing three identical collector-cum-storage type solar water heaters with 25, 50 and 150 mm air gaps. The heater with 50 mm air gap collects 11.64% and 7.72% more energy compared with heaters having 25 mm and 150 mm air gaps, respectively. The average overall efficiencies of the heaters are 52.5%, 57.8% and 54.1% having 25, 50 and 150 mm air gaps. A 50 mm air gap has, therefore, been found to be optimum. 相似文献