Sıfır Emisyonlu Yenilenebilir Enerji Üreten Yelkenli Bir Tekne İçin Sualtı Türbin Tasarımı

Abstract

Son yıllarda, rüzgar ve güneş enerjisi ile deniz ve gel-git akıntıları gibi yenilenebilir kaynaklardan elektrik enerjisi üretimi üzerine yapılan teorik çalışmaların ve uygulamaların hızlı bir şekilde arttığı görülmektedir. Bunlardan sualtı akıntı türbinleri, suyun değişik hareketlerinden yararlanarak enerji üreten sistemler arasında olan ve düşük akım hızlarında dahi enerji üretebilme yeteneğine sahip, okyanus ve denizlerde işletilen enerji üretme yöntemlerinden biridir. Bu çalışmada, yelkenli bir tekne üzerinde sabit bulunacak ve yelken seyri sırasında tekne gövdesi etrafındaki akıştan enerji elde edecek bir su altı akıntı türbininin, fonksiyon gereksinimleri doğrultusunda ön tasarımı ve detay tasarımı gerçekleştirilmiştir. Tasarım aşamalarında, su altı türbin kanatlarının dizaynı, analizi ve optimizasyonunda yaygın olarak kullanılan momentum kanat elemanı yöntemi (MBEM)’nden yararlanılmıştır. Ön tasarım ve detay tasarım sonucunda ortaya çıkan yatay eksenli sualtı türbin sistemi, bileşenleri ile birlikte gösterilmiştir. Bu sayede, üzerinde rüzgâr ve/veya güneş gibi yenilenebilir enerji kaynaklarından enerji elde edebilen, depolayabilen ve gerektiğinde bu enerjiyi kullanabilen donanıma sahip her yelkenli tekne için, güneş ve rüzgâr teknolojilerine göre daha fazla güç üretebilen, verimli, uzun ömürlü, kullanımı kolay ve yenilikçi bir ürün ortaya konmuştur.

Keywords

• Yenilenebilir enerji, sualtı akıntı türbini, momentum kanat elemanı yöntemi

Marine current turbine design for zero emission renewable energy producing a sailing boat

Abstract

In the recent years, rapid increase in theoretical studies and applications on electrical power generation from renewable sources, such as wind, sun, marine or tidal currents, can be encountered in the literature. Among these, marine current turbines, produce energy by taking the advantage of alternating motion of water, and have the ability to produce energy even at low flow rates, and are operated in oceans and seas as a renewable energy source. In this study, design of marine current turbine, to be installed on a zero emission sail boat consept as a prominent renewable energy source, is done. Firstly, the design requirements of marine current turbine to be installed on the sailboat are determined. So forth, prerequisites for two marine current turbines, at starboard and port, are turbine diameters to be less than 700 mm, design speed to be 3.1 m / s (6 knots), electrical power generation to be not less than 850 W, total appendage resistance to be not exceeding 5% of the ship resistance during the motor cruising and also 25% of the ship resistance during the sailing, in total, and weight of each turbine to be not exceeding 35 kg. Considering the prerequisites above, low Reynolds number turbine blade section profile FX63-167, also used wind turbine blade section with the highest CL/CD (lift coefficient/drag coefficient) ratio, is chosen. Nevertheless, considering manufacturing and productivity, changes in the geometry of trailing edge of the section is done. TSR, a substantial parameter for marine turbines, and turbine diameter data from available five marine current turbine in production, ranging in diameter 3.1-6.3 m are taken into account. For design, TSR and turbine diameter (D) are considered to be 3.4 and 0.5 m, respectively. TSR is an important parameter in turbine design. Turbine, under the boat, aims to convert energy to water flow that occurs on its body during the course of sailing. In the meanwhile, it is causes an additional resistance by acting as an appendage on sail boat. The additional appendage resistance reduces the speed of boat. It is inevitable. To overcome, the most efficient system can be developed by reducing it to the minimum. The additional appendage resistance on the sail boat occurs, since the two kinds of hydrodynamic forces are generated on turbine. The first hydrodynamic force is the viscous resistance component caused by flow around turbine geometry. The other hydrodynamic force is opposed thrust force, rotational thrust acting in the opposite direction of boat motion, occurring on turbine blades and trying to stop the boat. The opposed thrust increases in proportion with the increase in rotational speed of the turbine. Therefore, choosing lower TSR values is concluded in this study. A computer code, based on momentum blade element method, is used for blade geometry design and optimization. At the end of optimization, turbine speed (N), power coefficient (CP), tip speed ratio (TSR), torque (T), thrust (F) and theoretical power are calculated to be 460 rpm, 0.461, 3.882, 8.72 Nm, 827 N, 1383.5 W, respectively. The calculated final geometric values for the turbine blades are given. For the results obtained in pre-design calculations to be close to practice and actual, turbine mechanical design, including hub and pod parts, is also carried out. The reason for the system to be preferred as a folding system, is to minimize the flow-induced resistances during the motor cruising. A horizontal axis marine current turbine system with all components is designed and presented. As a result, an efficient, durable, easy to operate, and innovative product is presented for sailing boat which has capability to generate, accumulate and consume alternative energy by using solar and/or wind renewable energy sources.

Keywords

• Renewable energy, marine current turbine, momentum blade element method