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Spray cone angle and air core diameter of hollow cone swirl rocket injector
Get PDFABSTRACT : Fuel injector for liquid rocket is a very critical component since that small difference in its design can dramatically affect the combustion efficiency. The primary function of the injector is to break the fuel up into very small droplets. The smaller droplets are necessary for fast quiet ignition and to establish a flame front close to the injector head, thus shorter combustion chamber is possible to be utilized. This paper presents an experimetal investigation of a mono-propellant hollow cone swirl injector. Several injectors with different configuration were investigated under cold flow test, where water is used as simulation fluid. This investigation reveals that higher injection pressure leads to higher spray cone angle. The effect of injection pressure on spray cone angle is more prominent for injector with least number of tangential ports. Furthermore, it was found that injector with the most number of tangential ports and with the smallest tangential port diameter produces the widest resulting spray. Experimental data also tells that the diameter of an air core that forms inside the swirl chamber is largest for the injector with smallest tangential port diameter and least number of tangential ports.ABSTRAK : Injektor bahan api bagi roket cecair merupakan satu komponen yang amat kritikal memandangkan perbezaan kecil dalam reka bentuknya akan secara langsung mempengaruhi kecekapan pembakaran. Fungsi utama injektor adalah untuk memecahkan bahan api kepada titisan yang amat kecil. Titisan kecil penting untuk pembakaran pantas secara senyap dan untuk mewujudkan satu nyalaan di hadapan, berhampiran dengan kepala injektor, maka kebuk pembakaran yang lebih pendek berkemungkinan dapat digunakan. Kertas kerja ini mebentangkan satu penyelidikan eksperimental sebuah injektor ekabahan dorong geronggang kon pusar. Beberapa injektor dengan konfigurasi berbeza telah dikaji di bawah ujian aliran sejuk, di mana air digunakan sebagai bendalir simulasi. Kajian ini mendedahkan bahawa suntikan bertekanan tinggi menghasilkan sudut semburan kon yang besar. Kesan tekanan suntikan ke atas sudut semburan kon lebih ketara pada injektor yang mempunyai lubang tangen yang kurang Tambahan pula, injektor yang mempunyai jumlah lubang tangen yang paling banyak dan lubang tangen berdiameter paling kecil menghasilkan semburan yang paling lebar. Data eksperimental juga menunjukkan bahawa diameter teras udara terbesar terhasil di dalam kebuk pusar injektor yang mempunyai diameter lubang tangen terkecil dan jumlah lubang tangen yang paling kurang
NUMERICAL SIMULATION AND ANALYSIS OF COANDA EFFECT CIRCULATION CONTROL FOR WIND-TURBINE APPLICATION CONSIDERATIONS
Get PDFIn the efforts to investigate the performance of Coanda Jet in enhancing lift of an airfoil, a numerical study is carried out. Tangential jets that take advantage of Coanda effect to closely follow the contours of the body are considered to be simple and particularly effective in that they can entrain a large mass of surrounding air. This can lead to increased circulation in the case of airfoils, or drag reduction (or drag increase if desired) in the case of bluff bodies such as an aircraft fuselage. Critical review and analysis is also carried out for the application of Coanda Jet to optimize the aerodynamic performance of wind turbine, using the results of the numerical study and taking advantage of recent efforts to introduce Coanda effect as a novel circulation control technique. For this purpose a simple two-dimensional CFD modeling is utilized to reveal the key elements that could exhibit the desired performance criteria, in particular the lift enhancement and drag reduction, or a combination of both. Three dimensional configurations will be synthesized using certain acceptable assumptions, to compare such results with existing experimental data. Hence in this work the problem is idealized as basic airflow over a two-dimensional airfoil in subsonic flow; by the use of CFD technique, parametric study is carried out to arrive at plausible design considerations and to assess the practicability of Coanda jet in wind turbine design. Parametric study carried out shows the effectiveness of Coanda-jet in producing enhanced lift, which can contribute to increased torque in wind turbine application and increased axial thrust for propeller application. The numerical study also shows that appropriate trailing edge rounding off and tailoring the Coanda-jet thickness and momentum coefficient can produce enhanced lift to drag ratio.ABSTRAK : Dalam usaha untuk mengkaji prestasi Coanda Jet bagi mempertingkatkan daya angkat suatu aerofil, kajian berangka telah dijalankan. Tangen jet yang mengambil manfaat efek Coanda mengikut kontur permukaan dianggap mudah dan berkesan kerana ia dapat mengiring satu jisim besar udara sekeliling. Ini mendorong kepada penambahan edaran udara dalam kes aerofil, atau penurunan seret (juga penambahan seret jika diingini) dalam kes jasad tubir seperti fiuslaj pesawat. Ulasan kritikal dan analisis telah dijalankan bagi aplikasi Coanda Jet untuk mengoptimumkan prestasi aerodinamik turbin angin, menggunakan keputusan kajian berangka dan mengambil manfaat usaha memperkenalkan penggunaan efek Coanda sebagai satu teknik pengawalan edaran udara. Untuk tujuan ini, permodelan dua dimensi CFD telah digunakan untuk mendedahkan punca utama elemen yang dapat mededahkan kriteria prestasi yang diingini, khususnya peningkatan daya angkat dan penurunan seret, ataupun kombinasi kedua-duanya. Konfigurasi tiga dimensi akan disintesis menggunakan beberapa andaian yang boleh diterima, untuk membandingkan keputusan tersebut dengan data eksperimental yang sedia ada. Permasalahan dalam kajian ini diunggulkan sebagai aliran udara asas subsonik di atas aerofil dua dimensi; dengan menggunakan teknik CFD, kajian berparameter dijalankan untuk mendapat reka bentuk yang munasabah, dan mengkaji kebolehlaksanaan Coanda jet dalam reka bentuk turbin angin. Kajian berparameter menunjukkan keberkesanan Coanda-jet dalam menghasilkan peningkatan daya angkat, justeru menyumbangkan kepada peningkatan daya kilas dalam aplikasi turbin angin, dan juga penambahan tujah paksi dalam aplikasi bebaling. Kajian berangka ini juga menunjukkan pembundaran pinggir mengekor, pemilihan ketebalan Coanda-jet dan pekali momentum yang sesuai, akan menghasilkan peningkatan nisbah daya angkat terhadap seretan
PERFORMANCE DETERIORATION OF THERMOSIPHON SOLAR FLAT PLATE WATER HEATER DUE TO SCALING
Get PDFThe performance of Flat plate Solar Water Heater deteriorates within five to twelve years of their installation due to factors related to manufacturing, operating conditions, lack of maintenance etc. Especially, problem due to scaling is significant as it is based on quality of water used. The remaining factors are system dependent and could be overcome by quality production. Software is developed by incorporating Hottel Whillier Bliss (H-W-B) equation to ascertain the effect of scaling on system efficiency in case of thermosiphon system. In case of clean thermosiphon system, the instantaneous efficiency calculated at 1000 W/m2 radiation is 72 % and it drops to 46 % for 3.7 mm scale thickness. The mass flow rate is reduced by 90 % for 3.7 mm scale thickness. Whereas, the average temperature drop of water in the tank is not critical due to considerable heat content in water under severe scaled condition. But practically in case of major scale growth, some of the risers are likely to get blocked completely which leads to negligible temperature rise in the tank. ABSTRAK: Prestasi plat rata pemanas air suria merosot selepas lima hingga dua belas tahun pemasangannya disebabkan faktor-faktor yang berkaitan dengan pembuatannya, cara kendaliannya, kurangnya penyelenggaraan dan sebagainya. Terutama sekali, masalah disebabkan scaling (tembunan endapan mineral) perlu diambil berat kerana ianya bergantung kepada kualiti air yang digunakan. Faktor-faktor selebihya bersandarkan sistem dan ia boleh diatasi dengan mempertingkatkan kualiti pembuatannya. Perisian komputer dihasilkan dengan menggunakan persamaan Hottel Whillier Bliss (H-W-B) untuk menentukan kesan scaling terhadap kecekapan sistem dalam termosifon. Dalam sistem termosifon bersih, kecekapan seketika dikira pada 1000 W/m2 , pada kadar radiasi 72 % dan ianya jatuh kepada 46 % untuk ketebalan skala 3.7 mm. Kadar aliran jisim berkurangan sebanyak 90 % untuk ketebalan skala 3.7 mm. Manakala, penurunan suhu purata air di dalam tangki tidaklah kritikal, disebabkan oleh kandungan haba yang tinggi di dalam air di bawah keadaan kerak yang teruk. Tetapi dalam kes tumbesaran kerak yang genting, sesetengah penaik akan tersumbat sepenuhnya, mengakibatkan peningkatan suhu di dalam tangki boleh diabaikan
SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF SOLID-MICROPERFORATED PARTITION UNDER NORMAL INCIDENCE OF ACOUSTIC LOADING
Get PDFThe micro-perforated panel (MPP) is recently well-known as an alternative ‘green‘ sound absorber replacing the conventional porous materials. Constructed from a solid panel which provides a non-abrassive structure and also an optically attractive surface, there gives a feasibility to implement such a panel inside a vehicle cabin. This paper is the preliminary study to investigate the sound transmission loss (TL) of a solid panel coupled with a micro-perforated panel to form a doube-leaf partition which is already known as a lightweigth stucture for noise insulation in vehicles and buildings. The mathematical model for the TL subjected to normal incidence of acoustic excitation is derived. The results show that its performance substantially improves at the troublesome frequency of mass-air-mass resonance which occurs in the conventional double-leaf solid partition. This is important particularly for the noise source predominant at low frequencies. This can also be controlled by tuning the hole size and number as well as the air gap between the panels. ABSTRAK: Panel bertebuk mikro (micro-perforated panel (MPP)) kebelakangan ini dikenali sebagai alternatif penyerap bunyi yang mesra alam menggantikan bahan berliang lazim. Dibina daripada satu panel padu yang memberikan satu struktur tak lelas dan juga satu permukaan yang menarik, ia memberikan kemungkinan penggunaan panel tersebut di dalam kabin kenderaan. Tesis ini merupakan kajian permulaan dalam mengkaji hilang pancaran bunyi (sound transmission loss (TL)) oleh satu panel padu yang digandingkan dengan satu panel bertebuk mikro. Kaedah ini menghasilkan satu sekatan lembar kembar yang sememangnya dikenali sebagai struktur ringan penebat bunyi di dalam kenderaan dan bangunan. Model matematik diterbitkan untuk TL tersebut dengan menjalankan pengujaan akustik yang tuju normal. Keputusan menunjukkan bahawa prestasi meningkat dengan ketara pada frekuensi yang susah semasa resonans jisim-udara-jisim berlaku di dalam sekatan padu lembar kembar lazim. Ini penting terutamanya untuk sumber bunyi yang pradominan pada frekuensi rendah. Ia juga boleh dikawal dengan menalakan saiz dan jumlah lubang serta luang udara di antara panel-panel tersebut
Molecular Cloning and Production of Recombinant Phytase from Bacillus subtilis ASUIA243 in Pichia pastoris
Get PDFPhytase gene obtained from Bacillus subtilis ASUIA243 was cloned into a medium vector and transformed into E. coli. Restriction enzyme digestion was conducted to get blunt-ended phytase gene and ligated into the Pichia expression vector, pPICZαA. The recombinant vector, pPICZαA-243HPp was then linearized with PmeI and transformed into P. pastoris strain X33. Screening for multi copy gene number of transformants was done by re-plating the selected colonies on increasing concentration of zeocin. One positive clone, X243HPp#2 was then grown in BMGY media as the starting culture, followed by induction in BMMY media for protein expression study. The supernatant was then analysed by SDS-PAGE and Western blot method to check the protein expression.ABSTRAK: Gen fitase yang didapati daripada Bacillus subtilis ASUIA243 diklonkan sebagai vektor perantara dan berubah menjadi E. coli. Sekatan pencernaan enzim dijalankan untuk mendapatkan gen fitase berhujung tumpul dan diligatkan dengan vektor ekspresi Pichia, pPICZαA. Vektor rekombinan, pPICZαA-243HPp kemudian dilinearkan dengan PmeI dan berubah menjadi P. pastoris strain X33. Penyaringan untuk nombor gen berbilang salinan yang menjalani transformasi genetik dijalankan dengan menyalur semula koloni terpilih dengan penambahan kepekatan zeocin. Satu klon positif, X243HPp#2 kemudian dibiarkan hidup dalam perantara BMGY sebagai kultur permulaan, diikuti dengan aruhan dalam perantara BMMY untuk kajian penglahiran protein. Supernatan kemudian dikaji dengan SDS-PAGE dan kaedah sap Western untuk menyemak penglahiran protein.KEYWORDS: phytase, Bacillus subtilis, Pichia pastoris, gene cloning
Isolation of Lactic Acid Bacteria from Malaysian Non-Broiler Chicken (Gallus gallus) Intestine with Potential Probiotic for Broiler Feeding
Get PDFProbiotic supplement can function as substitute for antibiotics especially in the broiler chicken feeding which can form an integral part of organic farming. Broiler forms one of an important protein source in South East Asia. Lactic acid bacteria (LAB) are important inhabitants of animal intestine and are useful source of probiotic microorganisms. Non-broiler chicken could be an ideal source of probiotic microorganisms that can be utilized for large scale broiler feeding. Our studies have successfully identified, through morphological and biochemical tests, 11 LAB isolates from gastrointestinal tract of local non-broiler chicken (Gallus gallus). These isolates have the ability to utilize lactose as part of their metabolism process and all showed negative reactions on catalase test. Out of the eleven (11) isolates, three (3) isolates were Gram-positive cocci and remaining isolates were of Gram-positive bacilli. Three isolates (E4, E11 and E17) showed at least 10 mm inhibitory effects on disc diffusion test against pathogenic bacteria Salmonella typhimurium. The partial 16S rRNA gene sequencing showed that one isolate (E17) has 89% similarity with Lactobacillus rhamnosus. These LAB strains isolated from Malaysian domestic non-broiler chicken gastrointestinal tract can potentially be used as a component for probiotics formulation in poultry feeding.ABSTRAK: Makanan tambahan probiotik boleh berfungsi sebagai pengganti antibiotik terutamanya dalam pemakanan ayam pedaging yang akan membentuk bahagian kamiran dalam penternakan organik. Ayam pedaging merupakan sumber protein penting di Asia Tenggara. Bakteria asid laktik (lactic acid bacteria (LAB)) merupakan penghuni penting dalam usus haiwan dan merupakan sumber penting dalam mikroorganisma probiotik. Ayam bukan pedaging sesuai dijadikan sumber mikroorganisma probiotik agar dapat digunakan sebagai pemakanan ayam pedaging secara besar-besaran. Kajian telah berjaya mengenal pasti, melalui kaedah morfologi dan uji kaji biokimia, 11 LAB diasingkan daripada salur gastrousus ayam bukan pedaging (Gallus gallus). Pencilan ini berupaya menggunakan laktosa sebagai sebahagian daripada proses metabolisma dan semuanya menunjukkan kesan negatif terhadap ujian katalase. Daripada sebelas (11) pencilan, tiga (3) pencilan adalah kokus gram-positif dan pencilan yang lainnya adalah basilus gram-positif. Tiga pencilan (E4, E11 dan E17) menunjukkan sekurang-kurangnya 10 mm kesan rencatan terhadap ujian resapan cakera terhadap bakteria patogen Salmonella typhimurium. Sebahagian daripada urutan gen 16S rRHA menunjukkan bahawa satu pencilan (E17) mempunyai 89% persamaan dengan Lactobacillus rhamnosus. Strain LAB ini diasingkan daripada salur gastrousus ayam tempatan bukan pedaging, sesuai digunakan sebagai komponen untuk rumusan probiotik dalam pemakanan ayam-itik
Mammalian Cell Culture Clarification: A Case Study Using Chimeric Anti-CEA Monoclonal Antibodies
Get PDFThe extracellular expression of monoclonal antibodies (mAbs) in mammalian cell culture provides both opportunities and restrictions for the design of robust harvest and clarification operations. With advances in cell culture media and cell lines, it is now possible to achieve high titers of over 5 g/l for mAbs. However, Mammalian cells are sensitive to breakage due to shear stress that can result in release of proteases and other host cell proteins (HCPs) which eventually affects product stability and purity. There is larger number of mAbs undergoing clinical development and it has placed significant importance on platform technologies of process development. Generally, Centrifugation and microfiltration are the primary harvest techniques used in the industry and depth filtration is also used as a step operation on clarification. This study compares the unit operations; centrifugation, microfiltration and depth filtration for maximum recovery of monoclonal antibodies. The results have shown that the depth filtration as more suitable operation for mammalian cell culture clarification since it gives 96% recovery of mAbs in comparison to centrifugation and microfiltration. ABSTRAK: Pengungkapan luar sel dari antibodi monoklon (monoclonal antibodies ((mAbs) dalam kultur sel mamalia memberi ruang dan batasan terhadap reka bentuk penuaian yang cekap dan penerangan operasi. Dengan kemajuan dalam media sel kultur dan cell lines (produk yang berupa sel kekal yang digunakan untuk tujuan kajian biologi), kini adalah berkemungkinan untuk memperolehi titer tinggi melebihi 5g/l untuk mAbs [2]. Walaupun begitu, sel mamalia sensitif terhadap retakan disebabkan tegasan ricih yang menyebabkan pengeluaran protease dan hos sel protein yang lain, (host cell proteins (HCPs)) akhirnya mempengaruhi kestabilan dan keaslian produk. Terdapat mAbs dalam jumlah besar yang masih menjalani pembangunan klinikal dan sesungguhnya ini penting sebagai satu landasan teknologi dalam proses pembangunan. Umumnya pengemparan dan mikropenurasan merupakan teknik asas tuaian dalam industri dan penurasan dalam juga digunakan sebagai satu pengendalian langkah dalam penjelasannya. Kajian ini membandingkan operasi unit: pengemparan, mikropenurasan dan penurasan dalam untuk perolehan antibodi monoklon yang maksima. Keputusan menunjukkan penurasan dalam adalah operasi yang lebih sesuai untuk penjelasan kultur sel mamalia kerana ia memberikan perolehan 96 % mAbs berbandingkan dengan cara pengemparan dan mikropenurasan
TRACKING AND MONITORING OF TAGGED OBJECTS EMPLOYING PARTICLE SWARM OPTIMIZATION ALGORITHM IN A DEPARTMENTAL STORE
Get PDFThe present paper proposes a departmental store automation system based on Radio Frequency Identification (RFID) technology and Particle Swarm Optimization (PSO) algorithm. The items in the departmental store spanned over different sections and in multiple floors, are tagged with passive RFID tags. The floor is divided into number of zones depending on different types of items that are placed in their respective racks. Each of the zones is placed with one RFID reader, which constantly monitors the items in their zone and periodically sends that information to the application. The problem of systematic periodic monitoring of the store is addressed in this application so that the locations, distributions and demands of every item in the store can be invigilated with intelligence. The proposed application is successfully demonstrated on a simulated case study
TEMPERATURE CONTROL CIRCUIT FOR SURFACE ACOUSTIC WAVE (SAW) RESONATORS
No full textSurface Acoustic Wave (SAW) resonators are key components in oscillators, frequency synthesizers and transceivers. One of the drawbacks of SAW resonators are that its piezoelectric substrates are highly sensitive to ambient temperature resulting in performance degradation. This work propose a simple circuit design which stabalizes the temperature of the SAW resonator, making it independet of temperature change. This circuit is based on the oven control method which elevates the temperature of the resonator to a high temperature, making it tolerant to minor changes in ambient temperature.This circuit consist of a temperature sensor, heaters and a comparator which turn the heater on or off depending on the ambient temperature. Several SAW resonator were tested using this circuit. Experimental results indicate the temperature coefficient of frequency (TCF) decreases from maximum of 130.44/°C to a minimum of -1.11/°C.Â
ACOUSTIC EFFECTS ON BINARY AEROELASTICITY MODEL
No full textAcoustics is the science concerned with the study of sound. The effects of sound on structures attract overwhelm interests and numerous studies were carried out in this particular area. Many of the preliminary investigations show that acoustic pressure produces significant influences on structures such as thin plate, membrane and also high-impedance medium like water (and other similar fluids). Thus, it is useful to investigate the structure response with the presence of acoustics on aircraft, especially on aircraft wings, tails and control surfaces which are vulnerable to flutter phenomena. The present paper describes the modeling of structural-acoustic interactions to simulate the external acoustic effect on binary flutter model. Here, the binary flutter model which illustrated as a rectangular wing is constructed using strip theory with simplified unsteady aerodynamics involving flap and pitch degree of freedom terms. The external acoustic excitation, on the other hand, is modeled using four-node quadrilateral isoparametric element via finite element approach. Both equations then carefully coupled and solved using eigenvalue solution. The mentioned approach is implemented in MATLAB and the outcome of the simulated result are later described, analyzed and illustrated in this paper