Journal of King Saud University, Engineering Sciences最新文献

A simple analytical method for accurate prediction of the leakage reactance and leakage energy in high-voltage transformers 一种准确预测高压变压器漏抗和漏能的简单解析方法

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2022.06.002

Kamran Dawood, Güven Kömürgöz

Transformers are one of the most crucial pieces of equipment for the distribution and transmission of electric power. A high-voltage transformer plays a vital role to reduce power losses during the transmission of electricity. Leakage reactance plays a vital role in the working and stability of the transformer. The accurate prediction of the leakage reactance is a great asset to the transformer designers during the manufacturing stage to attain the dynamically optimum design of the transformer. In the literature, mostly given analytical techniques for leakage reactance calculations are applied to the transformers with the symmetric axial heights of the low-voltage, and high-voltage windings. Therefore, a proper analytical prediction for the leakage reactance in the transformer with asymmetric axial heights is needed to implement an optimized design. This paper proposes a new advanced method for an accurate calculation of the leakage reactance and leakage energies in different parts of the transformer with symmetrical and asymmetrical axial heights of the windings. Moreover, the finite element method and three different analytical methods are also compared with a new analytical technique for 5 real cases. For 2 cases, the proposed method’s results are also verified by experimental tests. The method’s accuracy in predicting the stored energy and leakage reactance of the high-voltage transformer is found to be more accurate and much simpler than the other analytical methods.

变压器是电力分配和传输最关键的设备之一。高压变压器在减少电力传输过程中的功率损耗方面起着至关重要的作用。漏电抗对变压器的工作和稳定起着至关重要的作用。准确的漏抗预测是变压器设计人员在制造阶段实现变压器动态优化设计的重要资产。在文献中，大多数给定的漏抗计算分析技术都应用于低压和高压绕组对称轴向高度的变压器。因此，需要对轴向高度不对称的变压器漏抗进行适当的解析预测，以实现优化设计。本文提出了一种新的先进方法，可以精确计算对称和不对称绕组轴向高度下变压器不同部位的漏抗和漏能。并针对5个实例，对有限元法和三种不同的解析方法进行了比较。对于2个案例，本文方法的结果也得到了实验验证。结果表明，该方法对高压变压器的储能和漏抗的预测精度比其他分析方法更准确、更简单。

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引用次数: 0

Effect of corrugated side-walls on plane turbulent wall jets in narrow channels 窄通道中波纹侧壁对平面湍流壁面射流的影响

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2022.09.002

Shazy Shabayek, Ehab Fattouh, Samir Ead

An experimental study is presented to investigate the effect of corrugated sidewalls on submerged wall jets in narrow channels. Experiments were performed in a flume 0.3 m wide, 0.5 m deep, and 13.5 m long. Jets issued under the gate with a fixed thickness of 2.5 cm and the tailwater depth was adjusted to 37.5 cm, giving a fixed tailwater depth ratio y_t/b_o = 15. Experiments were conducted for five slot Froude numbers 2, 3, 4. 5, and 6. The Reynolds number ranged between 24712 and 74136. Three sets of experiments of five runs each, were performed. In Set A, the experiments were performed with smooth sidewalls whereas in Sets B and C, two arrangements of corrugated sidewalls (with gaps and with no gaps) were used, respectively. Velocity profiles along the centerline of the flume, water surface profile and the eddy length were measured for each experiment. It was found that the corrugations with gaps caused the largest decay in the maximum velocity; however, the effect of the presence of the sidewall corrugations on the velocity decay diminishes with the Froude number. Furthermore, the corrugated sidewalls with no gaps were observed to induce more flow entrainment and therefore cause a steep increase in the jet discharge and momentum flux near the slot. However, the corrugated sidewalls with gaps induced more mixing and diffusion, farther downstream from the slot, and caused a faster decay in the jet discharge and momentum. The use of corrugated sidewalls is introduced in this study as an alternative technique, to corrugated beds, to be used for energy dissipation in narrow channels. The sidewall corrugations are easier to maintain as less debris/sediments are trapped in between the corrugations. In addition, if channel maintenance is required, the movement of the maintenance facilities on a smooth bed would be much easier than that on a corrugated bed. Moreover, the sidewall corrugations will not be damaged during the maintenance process.

通过实验研究了窄通道中波纹侧壁对淹没壁射流的影响。实验在一个宽0.3 m，深0.5 m，长13.5 m的水槽中进行。闸板下喷射，固定厚度2.5 cm，尾水深度调整为37.5 cm，固定尾水深度比yt/bo = 15。对2、3、4五个槽的弗劳德数进行试验。5和6。雷诺数在24712和74136之间。进行了三组实验，每组5次。在A组中，实验采用光滑侧壁，而在B组和C组中，分别采用两种排列的波纹侧壁（有缝隙和无缝隙）。每次实验均测量了水槽中心线速度分布、水面分布和涡流长度。结果表明，带间隙的波纹对最大速度的衰减最大；然而，侧壁波纹的存在对速度衰减的影响随着弗劳德数的增加而减小。此外，观察到没有间隙的波纹侧壁诱导更多的气流夹带，因此导致槽附近的射流流量和动量通量急剧增加。然而，有间隙的波纹侧壁在狭缝下游引起更多的混合和扩散，并导致射流流量和动量的更快衰减。在本研究中介绍了波纹侧壁的使用，作为波纹床的替代技术，用于窄通道中的能量耗散。由于较少的碎片/沉积物被困在波浪之间，侧壁波浪更容易维护。此外，如果需要进行通道维护，则在光滑床上的维护设备的移动将比在波纹床上的维护设备的移动容易得多。而且，在维护过程中不会损坏侧壁波纹。

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引用次数: 0

Energy performance evaluation of variable-speed milk refrigerator using propane (R290) 丙烷（R290）变频牛奶冰箱能源性能评价

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2022.05.006

Shailendra Kasera , Rajlakshmi Nayak , Shishir Chandra Bhaduri

Hydrofluorocarbons (HFCs) such as R134a, R410A, and R407C may not be the long-term solution for the HVAC & R industry due to their higher potential for global warming. People’s interest is now shifting toward alternate refrigerants like hydrocarbons (HCs). In this research paper, an experimental energy performance evaluation of a variable-speed milk refrigerator was conducted using propane (R290). R290 has good environmental and thermodynamic properties, and it is known as a fourth-generation refrigerant. Various performance parameters, such as Cooling Capacity, COP, and Compressor Energy Consumption, are analyzed using different speeds of DC compressor. The DC compressor has four different types of fixed speed along with one variable speed operation. The results achieved from the performance tests are presented and discussed.

氢氟碳化合物（hfc），如R134a、R410A和R407C，可能不是暖通空调的长期解决方案。因为它们对全球变暖的潜在影响更大。人们的兴趣正转向碳氢化合物（HCs）等替代制冷剂。本文以丙烷（R290）为原料，对一台变频牛奶冷冻机进行了节能性能评价实验。R290具有良好的环境性能和热力学性能，被称为第四代制冷剂。分析直流压缩机在不同转速下的制冷量、COP、压缩机能耗等性能参数。直流压缩机有四种不同类型的固定速度以及一种变速操作。介绍并讨论了性能测试的结果。

引用次数: 0

Removal of 2,6-dichlorophenol by adsorption with activated polypropylene nanofiber 活性聚丙烯纳米纤维吸附去除2,6-二氯苯酚

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2021.10.007

Duduku Krishnaiah , Arswitaa Baskaran , S.M. Anisuzzaman , Reddy Prasad D.M.

2,6-Dichlorophenol is an organochloride of phenol, and it is considered one of the emerging pollutants in wastewater due to its extreme corrosive nature and toxicity even at low concentrations. Melt-blown activated polypropylene (PP) nanofiber is a polymeric adsorbent and it is used to investigate the removal of 2,6-dichlorophenol. The high surface-to-volume ratio, high porosity, low surface energy, low density, and excellent mechanical characteristics of melt-blown PP nanofiber make it a suitable adsorbent. On the removal efficiency of 2,6-dichlorphenol, the influence of the initial concentration of 2,6-dichlorphenol, the weight of PP nanofiber utilized, temperature, and pH of the solution were examined. The Langmuir model, with a maximum adsorption capacity of 44.44 mg/g, was found to be the best match for the adsorption isotherm. Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy were used to examine melt-blown PP nanofiber before and after adsorption (FTIR). Through SEM images, it was proven that the average diameter of PP nanofiber after adsorption had increased up to 7.93

μ m .

Furthermore, the existence of phenolic chemicals on the surface of PP nanofiber is confirmed by FTIR analysis spectra. The pseudo-first-order model matched the kinetic data nicely.

2,6-二氯苯酚是苯酚的一种有机氯化物，由于其极强的腐蚀性和即使在低浓度下也具有毒性，被认为是废水中的新兴污染物之一。采用熔融吹塑活化聚丙烯（PP）纳米纤维作为高分子吸附剂，研究了其对2,6-二氯酚的去除效果。熔喷PP纳米纤维的高表面体积比、高孔隙率、低表面能、低密度和优异的力学特性使其成为一种合适的吸附剂。考察了2,6-二氯酚的初始浓度、聚丙烯纳米纤维的重量、温度和溶液pH对2,6-二氯酚去除率的影响。Langmuir模型最大吸附量为44.44 mg/g，与吸附等温线最吻合。采用扫描电镜（SEM）和傅里叶变换红外光谱（FTIR）对熔融吹制PP纳米纤维吸附前后进行了表征。通过SEM图像证明，吸附后的PP纳米纤维的平均直径增加到7.93 μm。此外，FTIR分析证实了PP纳米纤维表面存在酚类化学物质。拟一阶模型与动力学数据吻合较好。

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引用次数: 0

Exploring the Barriers to Implementing the Integrated Project Delivery Method 探索实施一体化项目交付方法的障碍

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2022.04.003

Rudhab S. Buk'hail, Ruqaya S. Al-Sabah

The willingness of Kuwait’s construction industry to implement the new and emerging delivery system, the Integrated Project Delivery method (IPD), was explored in this research. As general conclusions to the barriers to IPD are already established by existing literature, this research aims to identify the specific barriers to IPD by evaluating the willingness of non-IPD teams to implement the principles of IPD. Data was collected from members engaged in multiple construction projects located in Kuwait. Statistical analyses were performed on the collected data to examine differences and similarities in their responses. A Delay Index variable revealed that ongoing Design-Bid-Build (DBB) projects are suffering a delay that amounts to half their original construction duration and that is almost double the delay incurred on Design-Build (DB) projects, which suffered a lesser delay. The data was further analyzed based on the respondents’ project delivery system, project sector, years of experience, and project party. The results indicated that the majority of the respondents working in Kuwait were willing to implement most of IPD’s principles. Astonishingly, respondents working on DBB projects were more willing to implement the principles of IPD than those working on DB projects. The respondents from both the public and private sectors were equally willing. The main contractors were found to be less willing to implement IPD than all the other project parties. Moreover, the most prominent barriers prohibiting most respondents from implementing IPD was their unwillingness to sign a contract that includes liability waivers and one that includes IPD’s organizational hierarchical structure. The findings of this research contribute to the current body of knowledge by exploring the construction industry’s willingness to implement IPD and by simultaneously identifying the specific barriers to its implementation, as well as identifying where these barriers lie. These findings may be used as evidence by owners or industry pioneers in promoting the implementation of IPD in their respective organizations.

本研究探讨了科威特建筑行业实施新兴交付系统的意愿，即综合项目交付方法（IPD）。由于现有文献已经对IPD障碍做出了一般性结论，本研究旨在通过评估非IPD团队实施IPD原则的意愿来识别IPD的具体障碍。数据是从在科威特从事多个建筑项目的成员那里收集的。对收集的数据进行统计分析，以检查他们的回答的差异和相似之处。一项延迟指数变量显示，正在进行的设计-投标-建造（DBB）项目的延迟相当于其原始施工时间的一半，几乎是设计-建造（DB）项目延迟的两倍，后者的延迟较小。根据受访者的项目交付体系、项目部门、经验年数和项目方，进一步分析了数据。结果表明，在科威特工作的大多数答复者愿意执行IPD的大部分原则。令人惊讶的是，从事DBB项目的受访者比从事DB项目的受访者更愿意实施IPD原则。公营和私营机构的受访者都表示愿意。发现主要承包商比所有其他项目当事方更不愿意执行IPD。此外，大多数受访者实施IPD的最主要障碍是他们不愿意签署包括责任豁免和包括IPD组织等级结构的合同。这项研究的结果通过探索建筑行业实施IPD的意愿，同时确定实施IPD的具体障碍，以及确定这些障碍所在，为当前的知识体系做出了贡献。这些发现可能被业主或行业先驱用作在各自组织中促进IPD实施的证据。

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引用次数: 0

A simple control strategy and dynamic energy management for the operation of combined grid-connected and standalone solar photovoltaic applications 并网和独立式太阳能光伏电站运行的简单控制策略和动态能量管理

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2021.12.009

Rakesh Namani , Senthilkumar Subramaniam , SarojiniMary Samikannu , Madhusudanan Gurusamy

There is an increased focus on energy savings in low-voltage DC (LVDC) loads for home appliances. The use of LVDC for the local distribution system enables easier integration with renewable sources. This work presents the control and management of power flow to DC loads in grid-tied photovoltaic (GPV) systems. This system provides bi-directional flow of power from the DC load to the AC grid, using a pulse width modulation (PWM) technique, employing a voltage source inverter between the DC nano grid and the AC main grid. The bidirectional converter controls the active power transferred in both directions while operating at unity power factor (UPF). The modified three-level hysteresis current controller and the voltage controller are designed as the inner loop and the outer loop, respectively, to control the bi-directional power flow. The corresponding grid voltages and currents are used to generate the reference currents. The proposed system has been validated through MATLAB/Simulink simulations and experimentation on a prototype system developed in the laboratory controlled by the dSPACE 1103 real-time digital controller board. The results show that a regulated DC voltage is obtained for dynamic changes of source and load like in a real-time environment. The control strategy with its validation shows the efficacy of the proposed system.

家用电器低压直流（LVDC）负载的节能越来越受到关注。在本地配电系统中使用LVDC可以更容易地与可再生能源相结合。本文研究并网光伏（GPV）系统中直流负荷的潮流控制与管理。该系统使用脉冲宽度调制（PWM）技术，在直流纳米电网和交流主电网之间采用电压源逆变器，提供直流负载到交流电网的双向功率流。双向变换器控制在单位功率因数（UPF）下双向传输的有功功率。改进的三电平迟滞电流控制器和电压控制器分别作为内环和外环来控制双向潮流。相应的电网电压和电流被用来产生参考电流。通过MATLAB/Simulink仿真验证了该系统的有效性，并在dSPACE 1103实时数字控制器控制的实验室样机上进行了实验。结果表明，在电源和负载动态变化的实时环境下，可以得到一个稳定的直流电压。通过对控制策略的验证，验证了所提系统的有效性。

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引用次数: 0

A study of catalyst operating regimes using alumina-supported catalytic plates for CO oxidation in a microreactor 在微反应器中使用氧化铝负载催化板进行CO氧化的催化剂操作制度的研究

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2021.09.003

Rehana Kousar , Sang Hoon Kim , Ji Young Byun

The performance of a microreactor loaded with Pd/Alumina catalytic plates was tested for CO oxidation as a model reaction. A microreactor with a feasible joining method was designed for catalytic processes. Further, this study aimed to investigate the correlation of metal active phase and support thickness towards catalytic activity. Experiments on CO oxidation showed that the catalyst activity of the active material can be improved by controlling both the catalyst oxidation state and support thickness. Pd in oxide form (PdO) showed better catalytic activity as compared with that of the metallic Pd. Furthermore, given the same amount of deposited Pd, the catalytic activity was enhanced by decreasing the catalyst support thickness, which is due to an increase in the surface concentration of the active metal as a result of its shallow dispersion. The results showed that increasing film thickness within a certain range (∼30 µm) could significantly improve the catalyst activity.

以负载Pd/氧化铝催化板的微反应器为模型，对CO氧化反应进行了性能测试。设计了一种具有可行连接方法的催化微反应器。进一步研究了金属活性相和载体厚度对催化活性的影响。CO氧化实验表明，通过控制催化剂氧化态和载体厚度，可以提高活性材料的催化活性。与金属态钯相比，氧化态钯表现出更好的催化活性。此外，在沉积Pd量相同的情况下，降低催化剂载体厚度可以增强催化活性，这是由于活性金属的浅分散导致其表面浓度增加。结果表明，在一定范围内（~ 30µm）增加膜厚可以显著提高催化剂的活性。

引用次数: 0

Experimental investigation of mechanical sustainability and acoustic performance of fly ash cenosphere/epoxy polymer composites 粉煤灰空心球/环氧聚合物复合材料力学可持续性及声学性能试验研究

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2021.11.002

Sriharsha Hegde, N.H. Padmaraj, V. Siddesh, T.S. Sunaya, K. Adithya Kini, Vishal K. Sanil

Hollow spherical fly ash cenosphere is a by-product of the coal firing process in thermal power plants and nowadays has become a substitute for the other organic fillers in the composite industry. The present study investigates the mechanical and acoustic performance of cenosphere/epoxy-based polymer composites. Void content, Shore Hardness, Tensile, Flexural, Impact, and Acoustic studies were conducted on epoxy specimens containing 0, 3, 5, and 7% of cenosphere by weight. Surface morphology and failure pattern of the tensile failure samples were investigated using the scanning electron microscope technique. Incorporation of cenosphere into epoxy reduced the void content from 4.27 to 2.54 % and increased the Shore hardness from 80.8 ± 1.44 to 85.8 ± 1.78 when the filler content was increased from 3 to 5%. Impact strength, Tensile and Flexural modulus showed an incremental trend with the increase in the weight percentage of the cenosphere. Examination of the tensile failure surface showed the presence of twist hackles and better interlocking of cenosphere with epoxy matrix. The density of the specimens played vital role in sound absorption characteristics. The addition of the cenosphere in epoxy deteriorates the sound absorption behaviour of the material as compared to neat epoxy.

空心球形飞灰空心球是火电厂燃煤过程的副产品，目前已成为复合材料工业中其他有机填料的替代品。本文研究了空心球/环氧基聚合物复合材料的力学性能和声学性能。孔隙含量、邵氏硬度、拉伸、弯曲、冲击和声学研究分别对含有0、3、5和7%空心圈重量的环氧树脂试样进行了研究。利用扫描电镜技术对拉伸破坏试样的表面形貌和破坏模式进行了研究。当填料含量从3%增加到5%时，空心微球的加入使环氧树脂的孔隙率从4.27%降低到2.54%，邵氏硬度从80.8±1.44提高到85.8±1.78。冲击强度、拉伸模量和弯曲模量随空心球重量百分比的增加呈递增趋势。拉伸破坏表面的检测表明，空心微球与环氧树脂基体的联锁性能较好，且存在扭转刺。试样的密度对吸声特性起着至关重要的作用。与纯环氧树脂相比，在环氧树脂中加入空心球会使材料的吸声性能恶化。

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引用次数: 0

A new approach to predict the formation pressure using multiple regression analysis: Case study from the Sukharev oil field reservoir – Russia 多元回归分析预测地层压力的新方法——以俄罗斯苏哈列夫油田为例

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2022.03.005

Inna N. Ponomareva , Dmitriy A. Martyushev , Suresh Kumar Govindarajan

Formation pressure is an important indicator of field production potential. Currently, the common practice to estimate reservoir pressure is the hydrodynamic exploration test. This method requires shutting down the well, often for a long time. Such long shutdowns lead to less production from the reservoir and worsen the economics of the field. Here, we present the method for determining the pressure without shutting down the well by using statistical methods for such tasks. In this article, we describe the method of finding the formation pressure by using multidimensional multivariate analysis of the actual reservoir data from the Sukharev field. To build the model, several operational, geological, and reservoir properties at various stages of the field pressure were combined into a model to predict reservoir pressure. Results showed that with this simple statistical method, formation pressure varies in two distinctive stages. In the first stage, the formation pressure is influenced by the reservoir petrophysical parameters, whereas in the second stage, operational parameters were more prominent. Finally, three separate formations in the Sukharev field were examined to predict reservoir pressure, and the results were in very good agreement with the actual measured data. This confirmed that the method was practical and capable of predicting reservoir pressure at any time of the well's lifetime.

地层压力是油田生产潜力的重要指标。目前，估算储层压力的常用方法是水动力勘探试验。这种方法需要关闭井，通常需要很长时间。如此长时间的停产导致油藏产量减少，并使油田的经济效益恶化。在这里，我们提出了一种不需要关井就能确定压力的方法，该方法使用统计方法来完成此类任务。在本文中，我们描述了利用Sukharev油田实际储层数据的多维多元分析来确定地层压力的方法。为了建立该模型，将油田压力不同阶段的几个作业、地质和储层性质结合到一个模型中，以预测储层压力。结果表明，采用这种简单的统计方法，地层压力的变化可分为两个不同的阶段。在第一阶段，储层岩石物性参数对地层压力的影响较大，而在第二阶段，作业参数对地层压力的影响更为显著。最后，对Sukharev油田的三个独立地层进行了储层压力预测，结果与实际测量数据吻合良好。这证实了该方法的实用性，能够在油井生命周期的任何时间预测油藏压力。

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引用次数: 0

Tribological performance of volcanic rock (perlite)-filled phenolic-based brake friction composites 火山岩（珍珠岩）填充酚醛基制动摩擦复合材料的摩擦学性能

Q1 Chemical Engineering

Journal of King Saud University, Engineering Sciences

Pub Date : 2024-12-01 DOI: 10.1016/j.jksues.2021.12.010

Tej Singh

The present work investigated the influence of perlite on the tribological properties of phenolic-based brake friction composites. The composites were manufactured by mechanical mixing and compression moulding at different perlite loadings as 0%, 5%, 10% and 15% by weight and tribo evaluated following European regulations. Among the evaluated tribological properties, the highest coefficient of friction (0.430), the lowest fade (16.74%) and friction fluctuations (0.221) with the least friction variability (0.434) were registered in the composite with 5 wt.% perlite content. The recovery performance increased with perlite addition and remains highest (119.85%) in the composite with 15 wt.% perlite content. The friction stability, maximum disc temperature rise and wear resistance of the composites decreased with increased perlite content. The worn surface investigations revealed that the formation of contact plateaus largely influences such composites' tribological performance.

研究了珍珠岩对酚醛基制动摩擦复合材料摩擦学性能的影响。复合材料是通过机械混合和压缩成型制造的，在不同的珍珠岩载荷下，分别为0%、5%、10%和15%，并根据欧洲法规进行了摩擦评估。在评估的摩擦学性能中，珍珠岩含量为5 wt.%的复合材料的摩擦系数最高（0.430），褪色最小（16.74%），摩擦波动最小（0.221），摩擦变异性最小（0.434）。随着珍珠岩添加量的增加，复合材料的回收率有所提高，当珍珠岩含量为15 wt.%时，复合材料的回收率最高（119.85%）。随着珍珠岩含量的增加，复合材料的摩擦稳定性、最大盘面温升和耐磨性降低。磨损表面研究表明，接触高原的形成在很大程度上影响了复合材料的摩擦学性能。

引用次数: 0