A Twin Impulse Turbine for Wave Energy Conversion

M M Ashraful Alam,Hideki Sato,Manabu Takao,Shinya Okuhara,Toshiaki Setoguchi 한국유체기계학회 2016 International journal of fluid machinery and syste Vol.9 No.4

A twin unidirectional impulse turbine for wave energy conversion has been suggested in our previous study, and the performance under unsteady flow has been investigated by quasi-steady analysis. In the present study, the performance of twin impulse turbine under unsteady flow condition has been investigated by unsteady analysis of Computational fluid dynamics. As a result, the mean efficiency of twin unidirectional impulse turbine under unsteady flow is lower than the maximum efficiency of unidirectional impulse turbine. Moreover, it is verified that airflow goes backward in the reverse turbine in low flow rates.

진동 수주형 파력 발전을 위한 임펄스 터빈과 웰스 터빈 특성 연구

조관준(Kwan-Jun Jo),김지윤(Ji-Yoon Kim),한성훈(Sung-Hun Han),오진석(Jin-Seok Oh) 한국마린엔지니어링학회 2010 한국마린엔지니어링학회 학술대회 논문집 Vol.2010 No.10

This paper present a power characteristics of wells turbine and impulse turbine which are used in wave generation system of oscillating water column type. The output power characteristic of wells and impulse turbines is according to experiment results which obtained from the simulator. Wells and impulse turbines are installed in the same form of the buoy for testing the output characteristics. As a result, the initial starting characteristics of wells turbine is poor compared to the impulses turbine. But, output power of wells turbine is higher than impulse turbine. Generation power of impulse turbine is a lot more than wells turbine for buoy is selected according to the environment situation of installation sea and management feature of wave generation system.

Optimization of impulse water turbine based on GA-BP neural network arithmetic

Lingdi Tang,Shouqi Yuan,Yue Tang,Zhipeng Qiu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1

To develop an optimum design method for impulse water turbines with low specific speed, a representative impulse water turbine with low specific speed used in agricultural irrigation machinery was optimized with a combination of an orthogonal experimental design, a genetic algorithm, and a BP neural network in this study. Numerical calculation was applied to analyze interflow characteristics for optimized and original water turbines. Results showed that the internal flow characteristics of the optimized water turbine presented remarkable improvement compared with the original water turbine. Pressure distribution increased, the vortex strip in the draft tube was reduced remarkably, and impeller torque increased by 26 %. In addition, the optimized impeller was manufactured by 3D printing, and performance comparison was conducted between experiments of the optimized and original water turbines. The efficiency of the optimized water turbine reached 42.5 %, which exceeded the original water turbine’s of 8.5 %. With increasing rotating speed, maximum efficiency running point moved to a high flow rate, and highly efficient areas expanded. Internal characteristic analysis and a full-scale experiment for both water turbines showed that the performance of the optimized water turbine exhibited substantial improvement. The analysis and experiment also verified the theoretical correctness and feasibility of the proposed optimum design method.

7 MW급 증기터빈 기본형상설계 기법에 대한 연구

조수용,최범석,임형수 한국동력기계공학회 2019 동력시스템공학회지 Vol.23 No.2

Steam turbines have long been used for various applications such as power generation and transportation. However, the published data for the design technology are very limited due to the exclusive policy among leading manufactures. Therefore, in this study, a basic configuration design technique of steam turbine was studied. Since the inlet pressure of the steam turbine is very high, the impulse-type turbine and the reaction-type turbine are applied together to increase the efficiency. Hence, design techniques for impulse-type and reaction-type turbine have been established. In this design process, the output power was predicted based on the losses generated in the steam turbine internal flow path, and the optimum speed ratio was selected to perform a configuration design. To validate the developed design technology, a 6.6 MW power turbine was selected and the configuration designed using the established design technology was compared with the selected turbine. The design results showed fairly consistent configuration overall to confirm the accuracy of the developed design techniques.

A Twin Impulse Turbine for Wave Energy Conversion -The Performance under Unsteady Airflow-

Alam, M M Ashraful,Sato, Hideki,Takao, Manabu,Okuhara, Shinya,Setoguchi, Toshiaki Korean Society for Fluid machinery 2016 International journal of fluid machinery and syste Vol.9 No.4

A twin unidirectional impulse turbine for wave energy conversion has been suggested in our previous study, and the performance under unsteady flow has been investigated by quasi-steady analysis. In the present study, the performance of twin impulse turbine under unsteady flow condition has been investigated by unsteady analysis of Computational fluid dynamics. As a result, the mean efficiency of twin unidirectional impulse turbine under unsteady flow is lower than the maximum efficiency of unidirectional impulse turbine. Moreover, it is verified that airflow goes backward in the reverse turbine in low flow rates.

방파제 연계형 30kW급 파력발전용 임펄스터빈의 설계와 성능평가

김길원,홍기용,김경환,현범수 한국해양환경·에너지학회 2019 한국해양환경·에너지학회지 Vol.22 No.3

진동수주형 파력발전장치는 간단한 에너지변환 구조와 유지보수의 용이성 때문에 타 파력발전장치에 비해 상용화에 가장 근접한 장치이다. 본 논문은 도서지역의 방파제에 연계할 파력발전장치의 2차 에너지변환장치로서 임펄스터빈을 설계하고 성능평가 함을 목적으로 한다. 먼저 적지해역과 방파제의 규모에 적합한 기당 30 kW급 발전장치용 임펄스터빈의 개념설계를 수행하고 용수파력발전장치 설계에서 사용한 Hong et al.[2016] 의 연구방법론을 바탕으로 직경을 도출 하였으며, 수치해석을 통하여 다양한 설계변수의 민감도 해석을 진행하였다. 이를 바탕으로 도출된 기본 임펄스터빈의 형상에 더하여 날개 스팬방향으로 뒤젖힘각을 적용한 로터형상과 그 끝단에 링을 부착한 링형(Ring-type) 터빈 형상을 수치해석적 방법으로 제안하여 총 3개의 후보터빈을 도출하였다. 도출된 터빈들의 성능검증을 위하여 왕복유동이 재현 가능한 풍동에서 실험을 실시하여 각 터빈의 성능을 다양한 입력조건에서 평가하였고, 그중 링형 터빈이 설계점에서 최대 52.9%의 우수한 터빈 효율을 주는 것으로 확인하였다. The present study deals with the design and performance analysis of three different impulse turbines for 30 kW-class Oscillating Water Column (OWC) wave energy converter applicable to breakwater. Conceptual design was made by using the look-up table method of Hong et al.[2016] previously applied to Yongsoo Wave Power Plant. For the basic design, FLUENT-based numerical analysis tool was utilized to design a conventional-type impulse turbine by optimizing the design parameters such as number of blade, angle of guide vane, hub ratio and tip clearance. Two more models were designed by modifying the conventional-type to enhance the efficiency of turbines. Firstly, a ring-type turbine was proposed to minimize the vortex roll-up near the tip of rotor blade. The depth of penetration, thickness and length of ring were optimized numerically. Secondly, a sweep angle-type turbine designed by Yang et al.[2017] was considered as one of the candidates. Numerically designed three turbines were then validated experimentally using a specially-built reciprocating flow generator to simulate the wave movement inside OWC. It was found that while both ring-type and sweep angle-type turbines gave the better efficiency than the conventional-type, a ring-type turbine was finally selected as the best one which shows approximately 52.9% in peak efficiency.

충동터빈과 반동터빈 캐스케이드에서의 팁 간극 손실에 대한 비교 연구

박경욱(Kyungwook Park),정은환(Eunhwan Jung),송성진(Seungjin Song) 한국추진공학회 2008 한국추진공학회 학술대회논문집 Vol.2008 No.11

현재 항우연에서 개발 중인 우주발사체 터보펌프에 사용되는 터빈은 단단 충동터빈을 적용하고 있다. 우주발사체의 안정성을 위해 팁 간극을 비교적 많이 허용하고 있는데, 효율적인 면에서는 반동터빈 보다 다소 뒤지지만, 높은 출력비를 가지는 충동터빈이 팁 간극이 커질 때 어떤 효율경향을 나타내는지 알아보는 일은 의미 있는 일이다. 실험은 아음속 조건에서 실험하였고, 팁 간극을 각각 코드기준 1%~20%일 경우 충동과 반동 각각의 경우에 대하여 하류 전압손실을 측정하였다. 측정결과 팁 간극이 10%보다 더 커지면, 충동터빈이 오히려 전압손실량이 반동터빈보다 더 작아진다. 이것은 팁 간극이 비교적 큰 조건에서 충동터빈이 반동터빈보다 효율이나 출력비 면에서 더 나은 성능을 나타냄을 의미한다 Korea Aeronautics Research Institute (KARI) is developing a turbo pump that has 1-stage impulse turbine and relatively high tip clearance for safety. The objective of this research is to investigate the effect of reaction on tip clearance loss in axial turbines. Both cascades were tested in a subsonic wind tunnel. In each cascade, total pressure was measured for tip clearance ranging from 1% to 20% of chord. In results, increasing tip clearance, total pressure loss in reaction turbines is continually increased but impulse turbines keep almost same level of mass averaged total pressure loss. When tip clearance becomes more than 10% of chord, mass-averaged total pressure loss in impulse turbines is less than in reaction. This means that when tip clearance is more than 10% of chord, impulse turbines have better efficiency than reaction turbines.

노즐 통과 증기에 의한 블레이드에 작용하는 힘 특성

이병학(Byounghak Lee),박종호(Jongho Park) 한국소음진동공학회 2013 한국소음진동공학회 논문집 Vol.23 No.10

Last blades of LP turbine in nuclear power plant are the highly damaged part and suffered from nozzle steam impulses during the turbine operation. Nozzle impulse is known as a common cause of damage or failure in the turbine blade and results from steam flow distortions due to uneven steam flow patterns between the stationary blade vanes. If impulse force was continuously acting on the blade for a long time, crack or wear will occur in weak parts such as root. So, it is important to know variation of nozzle impulse during the blade moving. But there is no way to measure and estimate the magnitude and direction of nozzle impulse. Therefore, this study was performed to know the variation of nozzle impulse force according to the positions of the blade and to obtain blade equivalent force and torque. This results can be used for blade stress estimation.

7톤급 액체로켓 엔진 터보펌프 터빈 성능 연구

이항기,신주현,최창호 항공우주시스템공학회 2017 항공우주시스템공학회지 Vol.11 No.1

This study was performed to evaluate the turbine performance of a turbopump in the third stage engine of the Korea Space Launch Vehicle-II. The turbine is a supersonic impulse type with a single rotor. One nozzle is for starting and four remaining nozzles are for steady operation. A similarity test was carried out in the high air test facilities at the Korea Aerospace Research Institute. Test results showed that turbine efficiency changed much more from rotational speed variations than by pressure ratio variations. These results showed characteristics similar to other supersonic impulse turbines. 한국형 발사체 3단 엔진용 터보펌프 터빈에 관해 성능 시험을 수행하여 성능 특성 결과를 분석하였다. 터빈은 초음속 충동형 방식의 단단 형태이며, 노즐은 시동 노즐 1개와 정상 운전용 노즐 4개로 이루어졌으며, 부분 분사 형태로 되어 있다. 한국항공우주연구원 내의 고압 공기 터빈 상사 시험 설비를이용하여 상사 시험을 수행하였다. 시험 결과 효율은 회전수 변화에 크게 변화하며, 이에 반해 압력비변화에는 다소 작게 변화하는 초음속 충동형 터빈의 일반적인 특성을 보이고 있다.

30톤급 액체로켓 엔진용 터보펌프 터빈 성능시험

정은환(Eunhwan Jeong),박편구(Pyun Goo Park),김진한(Jinhan Kim) 한국추진공학회 2008 한국추진공학회지 Vol.12 No.1

Performance test of the 30-ton class liquid rocket engine turbopump turbine has been conducted using high pressure cold air. Overall performance of the two kinds of turbine rotors - rotor with knife-edged L.E blades and with rounded L.E blades - has been measured for various rotational speed and turbine pressure ratio. The effect of rotational speed and turbine pressure ratio on the turbine axial force behavior also has been measured in parallel. Test results have revealed that the efficiency of knife edged L.E. turbine is a little bit higher than that of rounded L.E. turbine. The axial force of the turbine varied linearly with respect to rotational speed and its magnitude largely depended on turbine pressure ratio.