• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.107-119
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• 2021

The cross-flow turbine is one of the most famous and widely used hydraulic power systems for a long time. The cross-flow turbine is especially popular in many countries and remote regions where off-grided because of its many benefits such as low cost, high efficiency at low head, simple structure, and easy maintenance. However, most modern turbines, including the cross-flow turbine, are unsuitable for the ultra-low head situation, known as less than 3m water head or zero head with over 0.5m/s flow velocity. In this study, we demonstrated a 20kW class inverted-type cross-flow turbine's performance. First, we reevaluated our previous studies and introduced how to design the inverted-type cross-flow turbine. Secondly, we fabricated the 20kW class inverted-type cross-flow turbine for the performance test. And then, we designed a testbed and installed the turbine system in the demonstration facility. In the end, we compare the demonstration with its previous CFD results. The comparing result shows that both CFD and real model fitted on guide vane angle at 10 degrees. At the demonstration, we achieved 42% turbine efficiency at runner speed 125 RPM.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.5
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• pp.363-370
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• 2013

Small scale hydropower is one of most attractive and cost-effective energy technologies for installation within sewage treatment plants. This study was conducted to evaluate the potential of a semi-kaplan micro-hydropower (MHP) system for application to sewage treatment plants with high flow fluctuations and a low head. The semi-kaplan MHP is equipped with an adjustable runner blade, and is without a guide vane, so as to reduce the incidence of mechanical problems. A MHP rating 13.4 kWp with a semi-kaplan turbine has been considered for Kiheung Respia sewage treatment plant, and this installation is estimated to generate 86.8 MWh of electricity annually, which is enough to supply electricity to over 25 households, and equivalent to an annual reduction of 49 ton $CO_2$. The semi-kaplan turbine showed a 90.2% energy conversion efficiency at the design flow rate of 0.35 $m^3/s$ and net head of 4.7 m, and was adaptable to a wide range of flow fluctuations. Through the MHP operation, approximately 2.1% of total electricity demand of Kiheung Respia sewage treatment plant will be achievable. Based on financial analysis, an exploiting MHP is considered economically acceptable with an internal rate of return of 6.1%, net present value of 15,539,000 Korean Won, benefit-cost ratio of 1.08, and payback year of 15.5, respectively, if initial investment cost is 200,000,000 Korean Won.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7729-7735
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• 2015

As plastic injection mold parts is suitable system mass production making mold. So thick steering wheel parts is desirable to carry out gas injection molding. Gas injection mold is skill to inject nitrogen gas postfilling melting raw material into mold. Gas injection mold have many advantage like retrenchment of material cost, upgrading the guality. etc. It was decided gate position to minimize warpage of parts analysis injection mold process using mold flow software and incase doing gas injection mold using normal p.p material. it occur big warpage. so it is object minimizing warpage of injection parts to change p.p material containing mineral 18% and removing fingering phenomenon trouble as changing gate position. Also in case carrying out gas injection mold, I did comparison and analysis to grasp shape flow in gas setting a standard gate after flowing in raw material. Through this study, I found out changing of thickness by parts shape and it can occur warpage of parts by plastic material even though it carry out gas injection mold and it had a direct influence on trouble of parts by gate position.