Study on Influencing Factors and Laws of Fuel Injection Consistency of Common Rail Injector

In order to study the influence of parameters of common rail injector internal components on cycle injection consistency, its simulation model is established by AMESim, and the model is validated by the experimental injection rate data. The effects of solenoid valve spring preload, gag bit lift, fuel discharge hole diameter, fuel inlet hole diameter, needle valve lift, needle valve preload and nozzle diameter on the change of injection quantity under different operating conditions are studied by simulation method, and the impact weight of each parameter on fuel injection consistency is analyzed. The results show that the preload of solenoid valve, fuel discharge hole diameter, oil inlet hole diameter, needle valve lift and nozzle diameter are the main parameters affecting the consistency of cycle injection. The percentages of five parameters influencing on the consistency of cyclic injection are 8.68-16.84%, 11.41-23.68%, 17.2086-37.74%, 12.772-18.34% and 9.69-37.27% respectively.

The Development of Germicidal Air Purifier by Employing Ultraviolet System in Controlling Airborne Bacteria

The nosocomial infection could be acquired through airborne disease in the hospital. However, only a particular health center in Indonesia carried out a complete, cautious prevention procedure by utilizing air purifiers due to cost problems. Thus, to minimize the number of nosocomial infections related to bacterial air pollutants, excellent tools with low cost are required to address this problem. We developed an ultraviolet light system within the air purifier at a low cost and the best way to eradicate pathogenic microorganisms in the healthcare center. The study was conducted at the Faculty of Medicine, Universitas Padjadjaran, Bandung in 2009–2010. The room prototype was built from a transparent glass material with two holes at the upper corner as an inlet and outlet pipeline canal. In the middle of the pipeline circulation, a vacuum pump, ultraviolet system, and a cooler were installed so the air will initially flow through those devices before being re-circulated into the room through the pipeline's inlet hole. A fan was set on the room floor, and several ten-centimeter apart, Petri dishes containing microbial growth medium were placed. The microbial colonies from the room with and without the installed ultraviolet system in the air purifier were then compared for analysis. The result showed that an air purifier equipped with an ultraviolet system killed microorganisms 73% more effective than the air purifier without an ultraviolet system (p<0.05). In conclusion, employing an ultraviolet system within the air purifier might be effectively killed microorganisms and ultimately reduce nosocomial infection. PENGEMBANGAN AIR PURIFIER RUANGAN DENGAN PEMANFAATAN SINAR ULTRAVIOLET UNTUK MEMBUNUH MIKROB BAWAAN UDARAInfeksi nosokomial dapat ditularkan melalui penyakit yang ditularkan melalui udara di rumah sakit. Namun, hanya rumah sakit atau pelayanan kesehatan tertentu di Indonesia yang melakukan prosedur pencegahan infeksi nosokomial secara optimal dengan memanfaatkan air purifier karena kendala biaya. Oleh sebab itu, untuk meminimalkan jumlah infeksi nosokomial yang terkait dengan bakteri pencemar udara diperlukan pengembangan air purifier yang baik dengan biaya yang murah. Kami telah mengembangkan sistem pembersih udara yang terintegrasi sinar ultraviolet dengan biaya rendah untuk mengurangi mikroorganisme patogen di ruang pelayanan kesehatan. Penelitian dilaksanakan di Fakultas Kedokteran, Universitas Padjadjaran, Bandung pada tahun 2009–2010. Prototipe ruangan dibuat dari bahan kaca transparan dengan dua lubang di sudut atas sebagai ruang instalasi pipa saluran masuk dan keluar. Pada bagian tengah sirkulasi pipa dipasang pompa vakum, sistem ultraviolet, dan pendingin sehingga udara akan mengalir melewati alat-alat tersebut sebelum disirkulasikan kembali ke dalam ruangan melalui lubang masuk pipa. Sebuah kipas dipasang pada prototipe ruangan dan setiap jarak sepuluh sentimeter ditempatkan cawan Petri yang berisi media pertumbuhan mikrob. Koloni mikrob dari ruangan model dengan dan tanpa sistem ultraviolet yang terpasang di air purifier kemudian dibandingkan untuk dianalisis. Hasil penelitian menunjukkan bahwa air purifier yang dilengkapi sistem ultraviolet membunuh mikroorganisme 73% lebih efektif daripada air purifier tanpa sistem ultraviolet (p<0,05). Simpulan, penggunaan sistem ultraviolet dalam air purifier efektif membunuh mikroorganisme dan pada akhirnya dapat mengurangi infeksi nosokomial.

Design and Construction of Indirect Solar Coffee Dryer

Drying is the process of removing moisture contents from solid. Solar drying refers to a technique that utilizes incident solar radiation to convert it into thermal energy required for drying purposes. This project presents the design, construction and performance of an indirect type solar dryer for coffee product. In the dryer the air inters into the solar collector from the atmosphere through air inlet hole. This air will be heated in the collector and then pass to the drying chamber through the hole. Then the air exhausts through the outlet hole at the top of the drying chamber. The system designed can handle a capacity of up to 50kg of wet coffee per m2 at a depth of 100 mm. The average sunshine at Bale Robe was found to be 12 hours per day. The daily solar insolation at the site was found to be 5.86kW/m2 of surface per day. By utilizing the solar collector in question and assuming a collector efficiency of 20 %, the total solar energy received is 5.86 kW-hrs/m2 /day or 46.88 kW-hours per day (assuming the sunshine hours per day to be 8 hours). This solar dryer has a collector efficiency of 39.1%, a pick-up efficiency of 49.3%, and a system efficiency of 32.2%. the collector area of the system is calculated to be 1.11m2 and the total length of 1000mm by 300mm. The drying chamber is essentially a cabinetry dryer and measures 1020mm × 800mm × 30mm. It accommodates a drying bin which acts as the holding compartment for the wet coffee to be dried. The base of the drying chamber is made of a block of wood material 50mm deep, since wood is a good thermal insulator. The wood must be well seasoned and pre-treated to ensure it is protected from the humid environment. The air outlet is fitted at the top of the drying chamber which serves as the exit for the moisture ridden air. It is important since it ensures that moisture does not condense at the top of the drying chamber and speeds up the rate of drying through creating the suction effect. The drying bin measures 800mm × 800mm × 20mm.

Numerical Simulation on the Flow Through the Inlet Hole of Fuel Assembly in a Fast Reactor

In fast reactor, the coolant flows into the inside of the fuel assembly through the inlet hole, so according to the design requirement, it is necessary to determine a suitable inlet hole model to make the pressure drop and velocity reasonably. In this paper, three hole models are researched and the distance of adjacent hole of every model is different. Based on the hydraulic test of fuel assembly in fast reactor, a simplification model of distribution header and assembly pin has been built. The computational fluid dynamic code—CFX was used to simulate the pressure field and velocity field of the assembly pin with k-e turbulence model. The results show when the distance of adjacent hole increases, the change of pressure and velocity in the hole area is gently, which makes little vibration. The research will be the reference for the following simulation work and assembly hydraulic test.

Design and Simulation of Piston Buffering Device for Impact Hammer

Aiming at the mispunch problem of emulsion impact hammer, the cone-type piston buffering structure was adopted to minimize the impact. Impact process simulation model of differential connection piston was built using AMESim software, the influences of different buffer length, conical angles and buffer clearance on the terminal velocity and pressure were analyzed according to the model and optimum parameters (half cone angle 5°, length 50mm as well as clearance 0.25mm) were determined. The collision progress between piston and the guide sleeve at 2m/s simulated by LS-DYNA software shows that the maximum stress is 674MPa which locates at at the edge of the liquid inlet hole of guide sleeve, and the maximum stress on interface is less than 400MPa, both of them area lower than the yield strength of materials,so the guide sleeve is of shock resistance. However, it is found to have rebounding phenomenon during the buffering process and the mispunch should be attentively prevented.

Study on Calcium and Magnesium Fouling of Vacuum Membrane Distillation

In this paper, calcium and magnesium fouling on membrane distillation process was investigated. The effect of less soluble salts with single component or multi component on flux and membrane fouling was examined, by means of synthesizing seawater. The results showed that the fouling caused by calcium carbonate and calcium sulfate was mainly formed by the attachment of the insoluble substance on the fibers. The calcium sulfate caused the blocking at inlet hole of the module. If there were less soluble salts with multi components in the feed, calcium carbonate was the main form of the fouling.