bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental Monitoring of Smog in Lahore Metropolitan Using GIS Technology
Authors: Mirza Ali Imam
Published: October 2022

Smog, a combination of polluted gasses or smoke with fog, brings a harmful breathing environment that mostly exists during the pre-winter season in Lahore. The smog episodes are prevailing over the city which are getting aggregated by smoky fumes, impurities, and dust particles. Severe smog episodes were observed over Lahore mainly during November and December 2019, resulting in adverse environmental conditions e.g., eye irritation, breathing difficulty, and creating very low visibility in and around Lahore. This study is based on eighty-five sample sites from all over Lahore city, to measure the Particulate Matter during smog season. In this study, the risk zones are demarcated based on land use and land covers during pre-winter seasons. It has been revealed through geospatial technology and the evaluation of weather data that local pollution has a greater contribution towards deteriorating the quality of air as compared to the contributions which are regionally active during the smog season. Spatial dispersion of smog has shown the local industrial and vehicular emissions as the major contributor of smog rather regional diffusion of pollutants.
Analyzing ML-Based IDS over Real-Traffic
Authors: Siyyal Shafqat Ali , Khuawar Faheem Yar , Saba Erum , Memon Abdul Latif , Shaikh Muhammad Raza
Published: October 2022

The rapid growth of computer networks has caused a significant increase in malicious traffic, promoting the use of Intrusion Detection Systems (IDSs) to protect against this ever-growing attack traffic. A great number of IDS have been developed with some sort of weaknesses and strengths. Most of the development and research of IDS is purely based on simulated and non-updated datasets due to the unavailability of real datasets, for instance, KDD '99, and CIC-IDS-18 which are widely used datasets by researchers are not sufficient to represent real-traffic scenarios. Moreover, these one-time generated static datasets cannot survive the rapid changes in network patterns. To overcome these problems, we have proposed a framework to generate a full feature, unbiased, real-traffic-based, updated custom dataset to deal with the limitations of existing datasets. In this paper, the complete methodology of network testbed, data acquisition and attack scenarios are discussed. The generated dataset contains more than 70 features and covers different types of attacks, namely DoS, DDoS, Portscan, Brute-Force and Web attacks. Later, the custom-generated dataset is compared to various available datasets based on seven different factors, such as updates, practical-to-generate, realness, attack diversity, flexibility, availability, and interoperability. Additionally, we have trained different ML-based classifiers on our custom-generated dataset and then tested/analyzed it based on performance metrics. The generated dataset is publicly available and accessible by all users. Moreover, the following research is anticipated to allow researchers to develop effective IDSs and real traffic-based updated datasets.
Floristic Composition, Biological Spectrum and Distribution Pattern of Floral Biodiversity in Jalalabad Taisot Valley, Gilgit Baltistan
Authors: Arif Sobia , Haider Sujjad
Published: October 2022

Jalalabad is a small village in Gilgit District in Pakistan, located around 20 km east of Gilgit city. Jalalabad village is one of the beautiful valleys located at 35°53.921 N latitude, 074°29.382 E longitude at an altitude of 1500. The present study was carried out from July-August 2021-2022 and was comprised of two main parts. The first part was floristic diversity, the second part was phytosociological studies. The collected specimens consist of (156) plant species that belonged to 119 genera and 49 families. The life forms of the collected species were 62 (72%) where Hemicryptophyte were dominant, 33 (22%) Therophytes, 14 (9%) Chaemophyte, 42 (27%) Phanerophyte and Geophytes were 4 (2%). The breakup of the habit categories shows that the herbs with 103 (66%) species were dominant to show the flora of the study area, followed by shrubs with 17 (10%) species which shows the flora of the study area. Subshrubs by 9 (6%) and trees 27 (22%) contained the flora of the study area. We studied three stands and in each stand, we placed twenty quadrate to recognize the dominant flora based on IVI. We recognized the dominant lifeform Hemicryptophytes and dominant taxa Thaymus linearis held at the highest value (64.259) based on IVI. The phytosociological studies provided all required information from each stand like dominant habit categories, dominant life forms, and dominant taxa in the study area.
Reliability Awareness Multiple Path Installation in Software Defined Networking using Machine Learning Algorithm
Authors: Majeed Muzammal , Amin Rashid , Ali Farrukh Shoukat , Ahmed Adeel , Hussain Mudassar
Published: October 2022

Link failure is still a severe problem in today's networking system. Transmission delays and data packet loss cause link failure in the network. Rapid connection recovery after a link breakdown is an important topic in networking. The failure of the networking link must be recovered whenever possible because it could cause blockage of network traffic and obstruct normal network operation. To overcome this difficulty, backup or secondary channels can be chosen adaptively and proactively in SDN based on data traffic dynamics in the network. When a network connection fails, packets must find a different way to their destination. The goal of this research is to find an alternative way. Our proposed methodology uses a machine-learning algorithm called Linear Regression to uncover alternative network paths. To provide for speedy failure recovery, the controller communicates this alternate path to the network switches ahead of time. We train, test, and validate the learning model using a machine learning approach. To simulate our proposed technique and locate the trials, we use the Mini net network simulator. The simulation results show that our suggested approach recovers link failure most effectively compared to existing solutions.
Associação entre a percepção da qualidade de vida, percepção do apoio familiar e recidiva de peso em mulheres com mais de 24 meses de cirurgia bariátrica
Authors: Fernandes Flávia Aline Lages , Diniz Amanda Cristina Tompson , Gomes Daniela Lopes
Published: October 2022

Introdução: A presença de reganho de peso (RP) e apoio familiar podem impactar a percepção da Qualidade de Vida (QV) e manutenção dos resultados no pós-operatório tardio de cirurgia bariátrica, o que torna relevante investigar a correlação entre esses fatores. Objetivo: Testar a associação entre percepção da qualidade de vida, percepção do apoio familiar e recidiva de peso em mulheres após 24 meses de cirurgia bariátrica. Método: Trata-se de um estudo transversal realizado com 50 participantes. Foram coletados dados antropométricos e aplicados questionários para avaliar a percepção da qualidade de vida e a percepção e satisfação com o apoio familiar pós-cirúrgico. Resultados: Houve perda de peso satisfatória após a cirurgia. Entretanto 46,0% da amostra apresentou recidiva de peso significativa. A percepção e a satisfação com o apoio familiar foram boas. Observou-se melhores percepções de qualidade de vida nos domínios relacionados aos aspectos físicos e piores relativos aos aspectos emocionais (p<0,000). O componente emocional geral e componente físico geral tiveram associação direta com a percepção de apoio familiar e com a perda de excesso de peso (%) e associação inversa com a recidiva de peso. Conclusão: É importante incentivar o apoio familiar após a cirurgia bariátrica, a manutenção do acompanhamento multiprofissional e o monitoramento da recidiva de peso, visando a manutenção dos resultados e melhor qualidade de vida.
Effects of Short-Period Exercise Training and Orlistat Therapy on Body Composition and Maximal Power Production Capacity in Obese Patients.
Authors: Colak R , Ozcelik O
Published: October 2022

We examined the effects of weight loss induced by diet-orlistat (DO) and diet-orlistat combined with exercise (DOE) on maximal work rate production (Wmax) capacity in obese patients. Total of 24 obese patients were involved in this study. Twelve of them were subjected to DO therapy only and the remaining 12 patients participated in a regular aerobic exercise-training program in addition to DO therapy (DOE). Each patient performed two incremental ramp exercise tests up to exhaustion using an electromagnetically-braked cycle ergometer: one at the onset and one at the end of the 4th week. DOE therapy caused a significant decrease in total body weight: 101.5+/-17.4 kg (basal) vs 96.3+/-17.3 kg (4 wk) associated with a significant decrease in body fat mass: 45.0+/-10.5 kg (basal) vs 40.9+/-9.8 kg (4 wk). DO therapy also resulted in a significant decrease of total body weight 94.9+/-14.9 kg (basal) vs 91.6+/-13.5 kg (4 wk) associated with small but significant decreases in body fat mass: 37.7+/-5.6 kg (basal) to 36.0+/-6.2 kg (4 wk). Weight reduction achieved during DO therapy was not associated with increased Wmax capacity: 106+/-32 W (basal) vs 106+/-33 W (4 wk), while DOE therapy resulted in a markedly increased Wmax capacity: 109+/-39 W (basal) vs 138+/-30 W (4 wk). DO therapy combined with aerobic exercise training resulted in a significant reduction of fat mass tissue and markedly improved the aerobic fitness and Wmax capacities of obese patients. Considering this improvement within such a short period, physicians should consider applying an aerobic exercise-training program to sedentary obese patients for improving their physical fitness and thereby reduce the negative outcomes of obesity.
UV Rays, the Prooxidant/Antioxidant Imbalance in the Cornea and Oxidative Eye Damage
Authors: Čejková J , Štípek S , Crkovská J , Ardan T , Pláteník J , Čejka Č , Midelfart A
Published: October 2022

In this minireview, the factors involved in the development of corneal injury due to an increased amount of UVB rays are summarized. Experimental studies have shown that an increased number of UVB rays leads to a profound decrease in corneal antioxidants (high molecular weight, antioxidant enzymes as well as low molecular weight, mainly ascorbic acid) so that a prooxidant/antioxidant imbalance appears. The decrease of corneal antioxidant protective mechanisms results in oxidative injury of the cornea and causes damage of the inner parts of the eye by UVB rays and by reactive oxygen species generated by them.
Birlikte Velayette Gönüllülük Prensibinin Yeri ve Anayasa Mahkemesi Kararının Değerlendirilmesi
Authors: ÖZTÜRK Barış Can
Published: October 2022

Ülkemizde uzun süre kabul görmeyen birlikte velayet, 1.08.2016 tarihinde yürürlüğe giren Avrupa İnsan Hakları Sözleşmesi Ek 7 No.lu Protokol ile kabul edilmiştir. Yargıtay 2. Hukuk Dairesi 20.02.2017 tarihli 2016/15777 E., 2017/1737 K. sayılı emsal kararıyla, birlikte velayetin uygulanabilirliğine hükmetmiştir. Birlikte velayetin hukukumuzda uygulanabilir hale gelmesiyle beraber uygulamada tarafların gönüllülük prensibi kapsamında bir diğer tabirle tarafların rızasının veya talebinin gerekip gerekmediği konusunda uyuşmazlıklar ortaya çıkmıştır. Bölge Adliye Mahkemesi (BAM) kararlarında birlikte velayet için tarafların gönüllülüğünün şart olup olmadığına ilişkin yeknesaklık bulunmamaktadır. Anayasa Mahkemesi Birlikte Velayet Kararında (Hilal Erdaş Başvurusu / Başvuru No: 2018/27658, 6.10.2021 Tarih) ise aile hayatına saygı hakkının ihlal edildiğine karar vermiştir. Mahkeme kararında tarafların görüşünün alınmaması, tarafların birlikte velayet taleplerinin olmaması, velayet konusunda taraflar arasında ihtilaf bulunmasını gerekçe göstermiştir. Bu kapsamda çalışmada birlikte velayetin amacı ve birlikte velayette gönüllülük prensibi; karşılaştırmalı hukuk, uluslararası belgeler ve Avrupa İnsan Hakları Sözleşmesi Ek 7 No.lu Protokol çerçevesinde değerlendirilmiştir. Yargıtay emsal kararının ve birlikte velayete ilişkin ilk olma özelliği taşıyan Anayasa Mahkemesi Hilal Erdaş Kararının gönüllülük prensibi kapsamında değerlendirilmesi yapılmıştır. Son olarak ise Anayasa Mahkemesi kararına ve olması gereken birlikte velayet düzenlemesine ilişkin görüşler sunulmuştur.
Israrlı Takip Suçu (TCK m. 123/A)
Authors: ÖZAR Süleyman
Published: October 2022

Israrlı takip fiili 5237 sayılı Türk Ceza Kanunu’nun 123/A. maddesinin yürürlüğe girmesiyle birlikte artık müstakil bir suçtur. Bu düzenleme, bireyin huzurlu bir ortamda, rahatsız edilmeden, belirli bir sükûnet, psikolojik rahatlık ve esenlik içinde yaşamını sürdürmesini ve bu suretle kişilerin manevi varlığını korumak ve geliştirme hakkını temin etmeyi amaçlamaktadır.
Israrlı takip, kasten işlenebilen neticeli bir suçtur. Huzur ve sükûn bozma suçunun aksine bu suç genel ve tamamlayıcı nitelikte değildir; işlendiğinde başlıbaşına uygulanır.
Çalışmada suçun TCK m. 123/A’daki düzenleniş şekline ve gerekçesine yer verilerek, hukuki konusu, faili, mağduru, unsurları, ortaya çıkış biçimleri, nitelikli halleri, yaptırımı ve muhakeme usulü incelenmiştir. Böylece, düzenlemenin kadına yönelik şiddetle mücadelenin etkinliğini artırma amacına hizmet edip etmediğinin de ortaya konulması planlanmaktadır.
Ceninin Yaşama Hakkı
Authors: KARASAÇ Eda Gülsüm
Published: October 2022

Yaşama hakkı, bireylerin sahip olduğu temel hak ve özgürlüklerin başında gelir. Embriyo ile ceninin yaşama hakkı ise, üzerinde ahlaki ve hukuki açıdan pek çok tartışmanın bulunduğu bir konudur. Ceninin insan ve kişi sayılıp sayılmayacağı tartışmaları bir yana, ceninin hak ehliyetini kazandığı ve kişiliğinin başladığı anın belirlenmesi cenine sağlanacak hukuki koruma bakımından büyük önem taşır. Kürtaj, çocuk düşürme ve düşürtme suçlarının yanında tıp ve biyoloji alanındaki teknolojik gelişmelere paralel olarak ceninin yaşama hakkının ihlaline yol açan durumlar artmıştır. Özellikle üremeye yardımcı tedavi yöntemlerinin uygulanmaya başlamasıyla birlikte, tüpte döllenen embriyoların yaşama hakkı konusunda doktrinde yeni tartışmalar doğmuştur. Bunun yanında yedek embriyolar, araştırma embriyoları, embriyolar üzerinde uygulanan genetik tanılama testleri de ceninin hukuki konumunun belirlenmesinin önemini ortaya çıkarmıştır. Buna karşılık ulusal mevzuat içerisinde embriyo ve ceninin hukuki statüsü hala belirsizdir. AİHM’nin vermiş olduğu kararlarda da yaşama hakkının ne zaman başladığı konusunda kesin bir yargıya ulaşılmış değildir. AİHM, çoğu kararında ceninin yaşama hakkını tartışmaya değer görmeyerek tartışmamıştır. Mahkeme konuyu tartışmaya değer bulduğunda ise doğumdan önceki aşamada ceninin yaşama hakkının olmadığına kanaat getirmiştir.
Hukukbilime Küresel Bir Bakış: William Twining
Authors: ÖZDEMİR Nadire
Published: October 2022

Bu çalışma anaakım hukuk felsefesi literatüründen ayrılan görüşlere sahip William Twining’in küresel hukuk yaklaşımını betimleyici bir şekilde tanıtmayı amaçlamaktadır. Çok mercekli, eleştirel, bağlamsal ve olguya dayalı bir bakış açısını temel alan Twining, küreselleşmenin ortaya çıkardığı sorunları ele almak üzere hukuk biliminin nasıl bir çerçeve sunması gerektiğini tartışmaktadır. Söz konusu çerçeve, 21. yüzyılın kendine özgü sorunlarıyla şekillenen hukuki meselelere çözüm sunmak açısından önem arz etmektedir. Çalışma Twining’in yaklaşımına ilişkin ana hatları çizmeyi amaçlamakta olup bu doğrultuda yazarın üzerinde durduğu temel kavram ve esaslar ele alınacaktır.
Experimental Evaluation of the Effectiveness and Safety of a New Propandic Acid Derivative Exhibiting Cardiotropic Action
Authors: Ivkin D. Yu. , Karpov A. A.
Published: October 2022

An entire cycle of preclinical studies of 4-[(3-ethoxy-3-oxopropanoyl)amino]benzoic acid (etmaben) exhibiting cardiotropic action was carried out. Its potential action mechanism and pharmacological effects, general toxic effects in acute and chronic experiments, specific types of toxicity (allergenicity, immunotoxicity, reproductive toxicity, mutagenicity), and pharmacokinetics were studied. The drug was found to have a pronounced cardiotropic effect and a positive safety profile, which justifies the launch of phase I clinical trials.
Evaluation of Single-Nucleotide Polymorphisms in Human Serum Albumin Associated with Alzheimer's Disease
Authors: Deryusheva E. I. , Litus E. A.
Published: October 2022

Human serum albumin (HSA) is a natural buffer for amyloid в peptide (Аβ), which is a key factor in the development of Alzheimer's disease (AD). An increase in HSA affinity to Аβ can be achieved via HSA saturation with low-molecular-weight ligands, such as serotonin or specific fatty acids. The conducted analysis of the genomic data of exomes (WES) associated with AD (ADSP database) revealed the presence of a single-nucleotide polymorphism of the HSA gene at the binding sites of ibuprofen, arachidonic and oleic acids. Research into the properties of the revealed genetic variants of HSA should be carried out to determine those variants that are susceptible to the modulatory action of HSA ligands, thus increasing its affinity to Aβ.
Dynamics of Changes in Acetylcholinesterase Activity in the Brain and Bood of Rats During Pharmacological Correction of Seizures Caused by Carbamate
Authors: Melekhova A. S. , Kubarskaya L. G. , Petrov A. N. , Bespalov A. Ya. , Verveda A. B. , Belskaya A. V. , Melnikova M. V.
Published: October 2022

To simulate a convulsive syndrome, phenylcarbamate was administered intraperitoneally at a dose of 1 mg/kg. Valproic acid aminoester (43 mg/kg), caramiphene (50 mg/kg), and diferidine (2 mg/kg) were investigated as potential anticonvulsant drugs. Blood and brain tissue for the determination of acetylcholinesterase (AСhE) were taken at 10, 30, 60 minutes, 6 and 24 hours after administration of the xenobiotic. In case of poisoning with reversible inhibitors of AChE and accumulation of acetylcholine in the CNS synapses (due to inhibition of AChE activity), only the initial manifestations of convulsive activity are caused, and other mechanisms not associated with AChE inhibition are responsible for the processes of further maintenance and recurrence of seizures.
Fermented Beet Juice with a Highly Active Symbiotic Consortium of Probiotic Lactobacillus Strains as a Specialized Product for Nutrition of People Working and Living in Extreme Conditions
Authors: Machulin A. V. , Kosarev I. V. , Khlebnikov V. S. , Vasilenko R. N. , Samoilenko V. A. , Pchelintsev S. Yu. , Abramov V. M.
Published: October 2022

The consortium of symbiotic strains of lactobacilli Lactobacillus plantarum MDIIE 2165 and Lactobacillus rhamnosus MDIIE 2166, deposited in the All-Russian Collection of Microorganisms (IBFM RAS), is the most suitable starter for obtaining a fermented beet juice (FBJ). These innovative probiotic lactobacilli ensure a deep processing of raw materials and allow a specialized food product with high organoleptic characteristics, biological value and adaptogenic properties to be obtained. FBJ can be used as a specialized nutrition product to improve the performance of athletes and people working and living in extreme conditions, as well as to prolong the professional longevity of the population.
Cultural and Spatial Negotiation in German Everyday Life: The Case of Turkish Students in Tubingen
Authors: KARAMEŞE Şeyma
Published: October 2022

This study mainly examines the place production processes of Turkish-origin youths in a German city. The main difference of this article is focusing on the dialectical relationship between space and identity by adding the space as a concept to the discussion of identity production processes of youth migrants in German context. As in the beginning of the socialization process, these youths in German schools are active agents, producing new places and transforming the existing places through negotiating their identities within the host country. In this study, an in-depth interview is conducted with 20 high school students in Tübingen. It is found that students not only produce their own identities but also create new existential spaces and reinterpret existing spaces. Cafes, restaurants, football fields, mosques/associations, Turkish lessons, mess halls, and celebration halls will be discussed with the concept of what I called “spatial negotiation”, inside and outside of the school. In there, students try to solve the existing tension between Turkish identities and German identities, and they are able to resolve this tension by producing new cultural forms. In other words, these places contribute to maintaining their own identities while at the same time creating new cultural values intertwined with other forms.
Multi-objective Optimization of A Three-shaft High Bypass Ratio Engine for EIS2050
Authors:   AECC Shenyang Engine Research Institute, Liu* Yixiong , Nalianda Devaiah ,   Cranfield University, Mo Da ,   AECC Shenyang Engine Research Institute, Wang Wei ,   AECC Shenyang Engine Research Institute, Wu Yunwu ,   AECC Shenyang Engine Research Institute, Du Qing ,   AECC Shenyang Engine Research Institute
Published: October 2022

In order to cope with the more stringent emissions goals, the aviation industry is dedicated to developing low emission and fuel-efficient engines. This paper aims to design an ultra-high bypass ratio three-shaft turbofan engine for EIS2050. A multi-objective optimization was performed using the genetic algorithm (GA) method, offering easy and convenient access to obtaining the desired engine. The critical parameters were identified and set as design variables to minimize the SFC and fuel burn. By recognizing the technology evolution for 2050, the design constraints were determined to ensure that the to-be-generated engine is practical. Afterwards, the optimization was undertaken in the developed GA optimizer with multi objectives, including cruise SFC, net thrust, engine weight and nacelle drag. Results show that the optimal engine deploys a high BPR and OPR, reaching 18.2 and 66.4 at the design point. The impressing 21.75% SFC reduction is at the cost of weight increase and drag penalty. However, aircraft level performance assessment reveals that combining the SFC improvement and lighter density materials, the optimized engine would provide a 28.83% drop in block fuel and save at least 2.95 million USD per year.
Turbomachinery Analysis and Design Using BodyForce Modeling in SU2
Authors:   Propulsion & Power Delft University of Technology, Bunschoten Evert C , Anand Nitish ,   Propulsion & Power Delft University of Technology, Pini Matteo ,   Propulsion & Power Delft University of Technology
Published: October 2022

Design optimization of turbomachinery components operating in nonuniform flow is computationally expensive using conventional computational fluid dynamic methods. The bodyforce model (BFM) enables to significantly reduce the computational costs associated to fluiddynamic simulations by substituting the physical blade row with a force field. In the research described in this paper, the capability of a BFM solver was tested by comparing the computational cost and model accuracy against the results obtained using bladed CFD (BCFD) analysis on the flow around the blades of a 1.5 stage axial turbine. The results from this analysis at grid convergence showed a reduction of CPU time and memory usage of a factor 900 and 78 respectively by using BFM, while the BFM model retained a relatively high accuracy with respect to bladed CFD results. The most significant offset in the trends was found in terms of mass flow rate and flow deflection, although their respective trends were accurately captured by the BFM.
Sequential ensemble multi-objective optimization algorithm and its application on the multi-working performance optimization of the variable cycle engine
Authors:   Northwestern Polytechnical University, Ye Yifan , Wang Zhanxue ,   Northwestern Polytechnical University, Zhang Xiaobo ,   Northwestern Polytechnical University
Published: October 2022

The numerical design optimization is becoming more and more popular as the rapid development of computer technology. The efficient global optimization (EGO) algorithm is one of the most popular optimization algorithm used in the investigation of aerospace engineering systems in recent years. Many researches optimize several conflicting performance objectives by using the improved version of EGO in recent years. The EGO algorithm is a Kriging-assisted optimization algorithm. Wherein, the Kriging surrogate model is used to predict the performance objectives. Thus the accuracy of the Kriging surrogate model affects the EGO algorithm performance. The multi-surrogate technology can build an ensemble surrogate model by combining different individual surrogates. The ensemble model shows better accuracy than the other individual surrogate model. Thus, this paper proposes a sequential ensemble multi-objective optimization (SEMO). In the proposed algorithm, the ensemble model is used to generate the new sample points during the optimization process. Also, a new Pareto conserve strategy is proposed to enhance the accuracy of the optimal solution set. To verify the performance of SEMO, four well-known multi-objective optimization mathematical functions is considered in this paper. Further, SEMO algorithm is applied to the multi-working performance optimization of the variable cycle engine.
Numerical Investigations on the Unsteady Leakage Flow and Heat Transfer Characteristics of the Turbine Blade Squealer Tip
Authors:   Xi’an Jiaotong University, JIANG Shijie , LI Zhigang ,   Xi’an Jiaotong University, LI* Jun ,   Xi’an Jiaotong University, SONG Liming ,   Xi’an Jiaotong University
Published: October 2022

The unsteady leakage flow and heat transfer characteristics of the turbine blade squealer tip was numerically investigated using three-dimensional Unsteady Reynolds-Averaged Naiver-Stokes (URANS) and standard k-ω turbulence model. The numerical simulated heat transfer coefficients of the turbine blade tip were well agreement with the experimental data. The accuracy of the numerical method was validated. The steady and unsteady leakage flow and heat transfer coefficient of the turbine blade squealer tip with and without film cooling was conducted. The unsteady leakage flow and heat transfer characteristics of the turbine blade squealer tip with film cooling design at three different blow ratios was numerically investigated. The obtained results show that the corner vortex and scraping vortex near the pressure side shows periodic fluctuation along the separation line of the leakage flow under the function of the pressure difference between the suction and pressure side of the blade tip, as well as the upstream vane unsteady wake flow. This unsteady flow behavior results in the fluctuation of the high heat transfer coefficients at the blade tip. The film cooling design along the camber line can effectively reduce the thermal load of the turbine blade squealer tip by comparison to without film cooling case. The time-averaged heat transfer coefficients of the turbine blade squealer tip reduce 9.0%, 12.4% and 13.2% at blowing ratio of .0.5, 1.0 and 1.5 comparison to without film cooling design in respective. The present work can provide the reference of the film cooling design for the turbine blade squealer tip.
Large-eddy simulation of shaped hole film cooling with the influence of streamwise pressure gradient
Authors:   Tsinghua University, Hu Kexin , Wang Qingsong ,   Tsinghua University, Su Xinrong ,   Tsinghua University, Yuan Xin ,   Tsinghua University
Published: October 2022

The complicated streamwise pressure gradient (SPG) environments in gas turbines affect the film cooling performance. In this research, shaped cooling hole with density ratio 1.5, blowing ratio 1.6, and acceleration coefficient, K=1e-6 is studied using Large Eddy Simulation (LES). LES results have been verified by experiment results. The differences between the Reynolds Average Navier – Stokes (RANS) results of zero pressure gradient (ZPG) and favorable pressure gradient (FPG) showed that the FPG keeps the jet closer to the wall surface, and the counter rotating vortex pair (CRVP) is compressed. The time-average and instantaneous flow field obtained from LES were analyzed to get the flow field details. Fast Fourier Transform (FFT) and Lumley triangle were used to analyze the vortices and the turbulence characteristics of the strong shear zone near the hole exit and downstream. The influences of FPG on horseshoe vortex, hairpin vortex and shear layer vortex were analyzed. The results showed that the hairpin vortex enhanced by FPG effect the film cooling performance of the downstream.
Effects of Squealer Width and Height on Aerodynamic Performance of Tip-Leakage Flow of Cavity Tips
Authors:   School of Energy & Power Engineering, Beihang University, He Xiaojuan , Zou Zhengping ,   School of Energy & Power Engineering, Beihang University
Published: October 2022

The scraping vortex (SV) is the dominant flow structure in the cavity tip gap. As the basic geometric parameters, it is of great significance to explore the influence mechanism of the squealer width and height on the evolution of SV. In this study, the influence mechanism of the squealer width and height on the SV evolution and aerodynamic performance in a typical transonic high-pressure turbine stage is investigated numerically, which is obtained by analyzing the influences of squealer width and height on the pressure distribution in the tip region, SV characteristics, and tip-leakage performance. The results show that decreasing squealer width or increasing squealer height reduces the transverse pressure gradient (TPG) in the cavity gap, which draws SV to the suction side squealer (SSS) and makes it easier to flow out of the cavity. Moreover, a thinner or a higher squealer leads to a smaller streamwise pressure gradient (SPG) in the cavity, and then the SV intensity enhances and size reduces accordingly. Extensive analysis reveals that there are optimum values of squealer width and height producing the most aerodynamic performance benefits.
IMPROVING THE FILM COOLING BY CONTROLLING THE VORTEX STRUCTURES
Authors:   College of Engineering, Peking University, Wang Qiuyin , Moosania Mostafa ,   College of Engineering, Peking University, Zhou* Chao ,   College of Engineering, Peking University
Published: October 2022

For film cooling, vortex structures downstream of the cooling hole determine the coolant mixing and the coverage surface area. The current study aims at identifying the vortex structures that can result in favorable cooling performance, based on which new holes are designed. The crescent hole with the convex leading edge can produce vortex structures that combine the features of two compound angle cylindrical holes and a middle vortex structure. These vortex structures prevent the coolant from lifting off from the surface at both low and high blowing ratios, and can result in uniform cooling effectiveness covering a larger area comparing to the cylindrical hole. To further improving cooling, another cooling hole is used to remove two small vortices on the lateral side by changing the up-convex to a down-convex crescent hole. This changes the rotational direction of the shear layer vortex at the lateral side of the hole, and produces a corotate vortex structure with the main anti-counter rotating vortex pair (anti-CRVP) which further enhances surface cooling effectiveness.
Analysis of Wheel Space Ingress in a One-Stage Axial Turbine
Authors:   Institute of Aerodynamics RWTH Aachen University, Hösgen Thomas , Meinke Matthias H. ,   Institute of Aerodynamics RWTH Aachen University, Schröder Wolfgang ,   Institute of Aerodynamics RWTH Aachen University
Published: October 2022

The ingress of main annulus gas into the wheel space of an one-stage axial flow turbine with 30 stator and 62 rotor blades is analyzed based on the results of a large-eddy simulation (LES) of the full 360  circumference of the turbine stage. The Navier-Stokes equations are solved using a finite-volume solver based on a Cartesian mesh with cut cells for the wall surfaces. The rotating blades are tracked by a level set, which is transported with a semi-Lagrangian method. The cut cell formulation at the boundaries with a flux redistribution method ensures conservation of mass, momentum, and energy. The LES is performed for a low cooling gas mass flow rate, at which several acoustic modes are excited in the wheel space. The focus of the analysis is on the determination of the main annulus gas ingress contributed by the various modes. For that purpose, the radial velocity component is filtered at the frequencies of the various modes and the time and azimuthally averaged main annulus gas ingress is computed as a function of the individual modes of the radial velocity fluctuations. The results show that the acoustic modes generating the largest amplitude of radial velocity fluctuations do not cause substantial ingress. This can be attributed to the relatively long time scale of the turbulent mixing of main annulus gas with the cooling gas compared to the time scale of the acoustic modes. Only modes at low frequencies generate substantial ingress, which is confirmed by the energy spectra of main annulus gas concentration variations.
EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF MIXED CONVECTION IN TURBINE CAVITIES FOR MORE FLEXIBLE OPERATIONS
Authors:   University of Oxford, Murat* Oguzhan , Rosic Budimir ,   University of Oxford, Tanimoto Koichi ,   Mitsubishi Heavy Industries, Egami Ryo ,   Mitsubishi Heavy Industries
Published: October 2022

Since the renewable sources, which have gained great attention due to the low-carbon policies, are inherently intermittent, the conventional power generation systems will be in use to meet the power demand. These systems, however, must be capable of operating along with renewables, which will lead to a need for more operational flexibility with frequent system ramps. Therefore, understanding and control of thermal stresses and clearances are essential for improving flexibility of conventional power plants. Computational fluid dynamics tools are of great importance in predicting the turbomachinery flows design since the direct measurements of detailed and spatial flow and temperature distribution are often not trivial in the real engines. During shut-down regimes of steam turbines, natural convection takes place along with relatively weak forced convection which is not strong enough to prevent a rising thermal plume leading to a non-uniform cooling in the turbine cavities. Although natural and forced convection have been studied separately in the literature, mixed type of flows in turbine cavities have not been investigated extensively. This paper provides unique experimental data set for validation and development of the predictive tools, which is generated from the detailed flow field measurements in a test facility designed for mixed type of flows in the turbine casing cavities with engine representative conditions. Additionally, large eddy simulations have been performed and validated against the generated experimental data, to gain deeper insight into the flow field. Thus, this paper offers a great insight in these complex flow interactions and unique experimental data for enabling the flexible operations and the development of advanced turbulence modelling.
The experimental study on the film cooling in the convergent-divergent nozzle with PSP technique
Authors:   Northwestern Polytechnical University, Liu Feng , Liu Cun-liang ,   Northwestern Polytechnical University, Ma Zhao ,   AECC Sichuan Gas Turbine Research Establishment, Guo Tao ,   Northwestern Polytechnical University
Published: October 2022

The effect of mainstream Mach number, including subsonic main flow at convergent section and supersonic main flow at divergent section of nozzle, on the film cooling effectiveness of cylindrical hole was studied in this paper. Two positions, which represent the different Mach number on the convergent-divergent nozzle, were chosen to arrange film hole at the convergent section and divergent section respectively. Pressure sensitive paint (PSP) technique was used to measure the film cooling effectiveness at five momentum ratios (0.05, 0.1, 0.15, 0.2 and 0.25). And numerical simulations were performed to analyse the related flow mechanism. The results showed that the increase of momentum ratio had slight effect on the film cooling effectiveness at low Mach number of mainstream in the convergent section. With the increase of the Mach number, the effect of momentum ratio on the film cooling effectiveness increases gradually. For the film hole at divergent section, although high momentum ratio led to secondary flow lift-off, the secondary flow lifting off was reattached to the wall and yielded wider spanwise coverage than that of convergent section.
PIV MEASUREMENTS OF TURBULENT FLOWS ALONG THE RIBBED SQUARE DUCT UNDER ROTATIONAL CONDITION
Authors:   Research Institute of Aero-Engine, Beihang University, Shi Jincheng , Li Haiwang ,   Research Institute of Aero-Engine, Beihang University, You Ruquan ,   Research Institute of Aero-Engine, Beihang University
Published: October 2022

In this paper, the change rule of flow characteristics along the ribbed square duct was investigated experimentally by two-dimensional time-resolved particle image velocimetry (TR-PIV). The Reynolds number, defined by main flow velocity(1.82m/s) and the hydraulic diameter(80mm), is set to 10000, the rotation numbers are 0, 0.13, 0.26, 0.39, 0.52, respectively. The blockage ratio and aspect ratio of the ribbed square duct are 0.1, 1 respectively. As the rotation number increased, The vortices structure on the suction side became larger and the attachment point moved backward. The situation on the pressure side was just the opposite, and this trend would develop along the duct. Furthermore, the parameters of different ribs along the duct varied greatly under the same rotation number. In the downstream ribs, the mainstream velocity pattern was more inclined to the pressure side, where the vortex structure was larger.
THE EFFECT OF IMPINGEMENT-EFFUSION COOLING STRUCTURE ON ADIABATIC FILM EFFECTIVENESS
Authors:   Tsinghua University, Wang Shanyou , Li Xueying ,   Tsinghua University, Ren Jing ,   Tsinghua University
Published: October 2022

Double wall cooling system for the vane is the most promising approach to meet the cooling demand of next generation turbine. The complex structure and heat and mass transfer process make many problems in double wall cooling unclear, which limits the development of double wall cooling in application. In this paper, the effect of impingement-effusion cooling structure on adiabatic film effectiveness is investigated numerically with two models, effusion film cooling-only and impingement-effusion cooling. Results show that the film effectiveness is not sensitive to the mass flow distribution of different rows of film hole and the effect of impingement structure on film effectiveness is very limited. It is therefore indicated that the film effectiveness of double wall cooling could be decoupled with complex heat transfer. It means the effect of impingement structure on adiabatic film effectiveness could be ignored when developing overall cooling models.
Generative Transfer Optimization for Aerodynamic Design
Authors:   Xi'an Jiaotong University, Guo Zhendong , Sun Wei ,   Aero Engine Academy of China, Song Liming ,   Xi'an Jiaotong University, Li Jun ,   Xi'an Jiaotong University, Feng Zhenping ,   Xi'an Jiaotong University
Published: October 2022

Transfer optimization, one type of optimization methods, which leverages knowledge of the completed tasks to accelerate the design progress of a new task, has been in widespread use in machine learning community. However, when applying transfer optimization to accelerate the progress of aerodynamic shape optimization (ASO), two challenges are encountered in sequence, that is, (1) how to build a shared design space among the related aerodynamic design tasks, and (2) how to exchange information between tasks most efficiently. To address the first challenge, a datadriven generative model is used to learn airfoil representations from the existing database, with the aim of synthesizing various airfoil shapes in a shared design space. To address the second challenge, both singleand multifidelity Gaussian processes (GPs) are employed to carry out optimization. On one hand, the multifidelity GP is used to leverage knowledge from the completed tasks. On the other hand, mutual learning is established between singleand multifidelity GP models by exchanging information between them in each optimization cycle. With the above, a generative transfer optimization (GTO) framework is proposed to shorten the design cycle of aerodynamic design. Through airfoil optimizations at different working conditions, the effectiveness of the proposed GTO framework is demonstrated.
Generative Design of Internal Cooling Channels for Gas Turbine Blades
Authors:   Shanghai Jiao Tong University, Wang Xinxing , Yu Bocheng ,   Shanghai Jiao Tong University, Lu Zijie ,   Shanghai Jiao Tong University, Wang Binyan ,   Shanghai Jiao Tong University, Yang* Li ,   Shanghai Jiao Tong University, Li Weihong ,   Hong Kong University of Science and Technology
Published: October 2022

Conventional cooling channels inside air-cooled turbine blades were mainly constructed by regular geometric features such as pin-fins, ribs or dimples. The heat transfer potential of such features were already well exploited by the literature in the past few decades, and the cooling performance of turbine blades has reached a bottle neck. Instead of manually crafting regular geometry shapes and making combinations, a novel concept arising in recent years advocated to generate complicated geometries by rules, which was named generative design. This study proposed a geometry generation method based on bionic rules and partial differential equations. The concept was inspired by the self-organization phenomenon of natural objects. Heat transfer evaluation was conducted on multiple geometries generated in different domains, with different length scale and with different equation parameters. The results indicated a wide range of heat transfer performance that generatively designed cooling channels could provide. Geometries with low porosity or high connectivity of the solid tended to have better heat transfer performance. Complex geometries were generated successfully under the control of the initial value of the phase filed. This method was expected to produce new possibility for enhancing cooling performance of turbine blades.
EXPERIMENTAL STUDY OF TIME-RESOLVED FILM COOLING EFFECTIVENESS OF COMPOUND-ANGLED FAN-SHAPED FILM-HOLE AT CURVED WALL
Authors:   University of Science and Technology of China, Zhang Tiao , Pu Jian ,   University of Science and Technology of China, Wang Jian-hua ,   University of Science and Technology of China
Published: October 2022

Besides time-averaged cooling performances concerned in previous literature, unsteady film cooling jets require cooling unsteadiness level should be an additional parameter to evaluate the benefits of different film cooling geometries. In the present work, a time-resolved infrared thermal image system was applied to acquire the time-averaged film effectiveness fields and two-dimensional contours of standard deviation (SD) of effectiveness, in terms of typical fan-shaped film-holes in limited by the actual blade geometry. The level of SD directly reflects the strength of cooling unsteadiness, determined by the temporal variations of footprints of dominated secondary-vortices at walls. Deep discussions of the combined influences of compound angle (CA), wall curvature and cooling air flowrates on the cooling unsteadiness level and trends in time-averaged film effectiveness were conducted, to acquire the proper cooling scheme in different local regions of blade. Three typical CAs of 0°, 30° and 60° were chosen. Convex, concave and flat walls with typical dimensionless curvatures were designed to simulate three different local regions of blade. Blowing ratio (BR) of coolant-to-mainstream was varied from 0.5 to 3.0. The detailed comparisons of experimental results revealed the complex trends in film effectiveness and cooling unsteadiness level with CA, BR and wall curvature, which have been listed in Conclusions. In general, the shaped-hole with CA= 30° is significantly proper to reduce the local hot-spots at the convex and nearly-flat walls, due to the highest film effectiveness and lowest cooling unsteadiness level. However, the angled shaped-holes at the concave wall can produce the high-level unsteadiness, increasing the risk of thermal damage and bringing to a new challenge of modifications of hole-geometry to reduce the cooling unsteadiness level while keep the high effectiveness.
Research status and development trend of rotating internal cooling of a gas turbine blade
Authors:   Tsinghua University, Guo Xinxin , Li Xueying ,   Tsinghua University, Ren Jing ,   Tsinghua University
Published: October 2022

Blade internal cooling is crucial for gas turbine thermal efficiency improvement. As an essential component of gas turbine, the investigations on cooling performance of rotor blade is a must. In the paper, the research status of turbine rotor blade internal cooling is illustrated in term of the effect of Coriolis force, buoyancy and cooling channel structure on the cooling performance of rotation internal channel. The three factors have significant influence on the internal cooling performance. Moreover, the development trend of rotating internal cooling is introduced, and novel structure design concept of double wall inner cooling is introduced and simulated as well. The result indicates that the overall heat transfer of the change orientation cooling channel performs better compared to conventional serpentine U-shaped channel due to Coriolis effect. Therefore, that the novel structure cooling channel is promising in the future application.
Effects of hole arrangement and trenched hole on multirow film cooling
Authors:   Zhejiang University, Wang Wen , Cui Jiahuan ,   Zhejiang University, Qu Shaoxing ,   Zhejiang University
Published: October 2022

Multirow film cooing is an advanced cooling method to provide large surface cooling for gas turbine components exposed to high temperature. In this paper, the efficiency of multirow film cooling under different configurations is investigated numerically. The geometrical parameters including the hole arrangement, hole orientation and trenched hole are considered. The numerical setup is validated before the cooling performance of different configurations is predicted and analysed. The results showed that the staggered arrangement is not always beneficial to the cooling efficiency. For standard hole, the inline arrangement with opposite compound angles provides the best cooling efficiency. The trenches contribute a lot to the multirow film cooling. For all the configurations investigated, the cooling efficiency of multirow trenched holes is higher than the largest cooling efficiency obtained by standard holes. The configuration of inline compound angle holes with opposite orientation embedded in trenches is the best design throughout all the investigated configurations.