Turbo solenoid vana
Turbo solenoid valve
Yazar: YAŞAR MUTLU
Danışman: DR. ÖĞR. ÜYESİ MURAT ÇAKAN
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Makine Dinamiği, Titreşimi ve Akustiği Bilim Dalı
Derece: Doktora, 2018
Konu: Makine Mühendisliği = Mechanical Engineering
Dizin: Eksenel akış = Axial flow

Özet:
Bu çalışma patentli bir sistem olan turbo solenoid vana sistemi için türbin tasarımından oluşmaktadır. Turbo solenoid sistemi akış otomasyonunda akış kontrolü için kullanılan yeni geliştirilmiş bir sistemdir. Bu sistem kendine yeten bir sistem olup bu sistem sayesinde akış kontrolü enerji ve kontrol için kablo kullanmadan mümkün olacaktır. 
Turbo solenoid sisteminin en önemli parçalarından biri türbindir. Bu sebepten dolayı bu çalışmanın ana amacı HAD analizlerini kullanarak turbo solenoid vana sistemine uygun bir boru içi türbin tasarımı yapmaktır. Bu kapsamda boru içi çalışmalarına uygun olan farklı tip türbinler incelenmiştir. Sonuç olarak Darrieus, Gorlov ve Lucid® türbinlerinin bu uygulama için daha uygun olacağı kanaatine varılmıştır ve bu bağlamda HAD akış analizlerine tabi tutulmuştur. HAD analizlerinde türbin tipi dışında ayrıca kanatların burkulma açısı ve kanatların profil tipinin türbin performansı üzerine etkisi incelenmiştir. Aynı ölçüye ve NACA0018 profiline sahip türbinler üzerine yapılan analizler sonucunda Lucid® türbininin en yüksek moment değerini ürettiği ve buna karşılık boruda en yüksek basınç düşüşüne de sebep olduğu anlaşılmıştır. Diğer yandan 10° burkulmuş Gorlov türbinin Lucid® türbinine göre %31,3 daha az moment ürettiği ancak buna karşılık %51,4 daha az basınç düşüşüne sebep olduğu görülmüştür. 
Kanat profili etkisini incelemek için Darrieus türbini NACA0021 ve NACA0015 profilleri ile irdelenmiştir. Kıyaslamalar sonucunda NACA0021 profiliyle olan türbinin NACA0018 profiline sahip türbine göre %1,5 daha az moment ürettiği ama %3,3 daha fazla basınç düşüşüne sebep olduğu görülmüştür. Buna karşılık NACA0015 profiline sahip türbinin NACA0018 profiline sahip türbine göre %9 daha fazla moment ürettiği ve %1,4 daha fazla basınç düşüşüne sebep olduğu görülmüştür. 
Kanat burkulma açısının performans üzerine etkisini incelemek için 20° burkulmuş Gorlov türbini incelenmiştir. Sonuç olarak 20° burkulmuş Gorlov türbininin 10° burkulmuş Gorlov türbinine göre %19,1 daha yüksek bir moment ürettiği ve %5,5 daha az basınç düşüşü ürettiği sonucu elde edilmiştir. 
Son olarak 20° burkulmuş Gorlov türbini NACA0015 profiliyle analiz edilmiştir. Analizler sonucunda bu tip türbinin en yüksek momenti üreten Lucid® türbinine göre sadece %4,7 daha az moment ürettiği ve buna karşılık %49,3 daha az basınç düşüşüne sebep olduğu sonucuna elde edilmiştir. Analizler sonucunda NACA0015 profiline sahip 20° burkulmuş Gorlov türbininin turbo solenoid sistemine en uygun türbin olacağı sonucuna varılmıştır. 
Çalışmaların devamında turbo solenoid sistemi için uygun görülen NACA0015 profiline sahip 20° burkulmuş Gorlov türbininin hızlı prototipleme yöntemiyle üretimi yapılmıştır. Üretilen bu türbinle deneysel çalışmalar yapılarak, sayısal analiz sonuçlarının doğruluğu araştırılmıştır. İncelemeler sonucunda moment üretimi kıyaslamalarında yatak ve sızdırmazlık elemanlarından kaynaklandığı bilinen %10'luk bir fark gözlemlenmiştir. Benzer şekilde basınç kaybı kıyaslamalarında kanat yüzey sürtünmelerinden kaynaklandığı bilinen 1,9 kPa'lık bir fark gözlemlenmiştir.

Abstract:
Fluid control technology is a field with numerous applications in the industry, the service industry and for domestic uses. On the other hand, with the proliferation of concepts such as the industry 4.0 industrial revolution in the world and the internet of things, the interest and need for smart systems is increasing day by day. Two issues have gained importance in this respect, particularly by the routing of current user trends: energy efficiency and self sufficiency.
Especially in regions where electrical power is difficult to deliver, it is very important to provide the energy of the flow automation equipment that will be used for flow control in remote areas. Cable networks established for the energy supply and control of flow automation equipment in installations, such as international crude oil and natural gas transmission lines, large power plants, petrochemical plants and petroleum refineries bring serious installation, repair and maintenance costs to the enterprises. The failure of fluid control equipment to operate properly in such facilities may sometimes lead to adverse situations. Because of this reason, it is ensured that these systems work continuously in a healthy way with the repairs and maintenance that are perpetually made in the enterprises. In areas of explosion risk in particular, these costs are increasing even more, due to the dedicated equipment that needs to be used, and any malfunction can lead to greater catastrophes.  
The numerical and experimental study presented here is concerned with the establishment of a locally self-sustaining system for the control of the fluid control equipment, producing energy with the aid of the fluid to be controlled. Thanks to this system, automation processes will become much easier, and it will be possible to provide only wireless power and flow control with wireless communication, especially in big pipe areas without any cabling system. 
In the Turbo Solenoid Valve System, first of all, rotation is obtained from the running fluid by means of a turbine; in this way, a special electrical generator is operated and the solenoid valve is energized by the electric power obtained. A battery system is used to keep the required electrical energy at an appropriate level and to ensure that the control system operates in all situations. 
The operation of the system is briefly as follows: the fluid is driving the turbine, the turbine drives the generator and the alternative current power obtained from the generator is converted by a rectifier and a regulator to a constant voltage, which charges the battery and powers the control system. In case of both the first operations and insufficient power generation, the battery will provide the necessary energy. It will also feed the control system in standby mode, which requires a certain amount of energy, especially for wireless data communication. 
As a result of the experimental measurements made, it has been observed that a 4W power source is sufficient for a latching solenoid valve that opens or closes in 12 seconds. In the experiments performed, the Wi-Fi system's power consumption and the system's incapability of generating power when the valve is closed have been considered. 
As is well known, the prime equipment used to generate electric power from the flow energy is turbines. The turbines can be divided into two main groups according to the position of the turbine's axis of rotation in the flow: 1) Axial Flow Turbines, 2) Cross Flow Turbines. In axial flow turbines, the turbine's axis of rotation is parallel to the flow direction. In order to obtain a good efficiency in such turbines, the direction of the rotor must always be parallel to the flow. In cross-flow turbines, the flow direction is perpendicular to the turbine's axis of rotation. In such turbines, the axial direction of the turbine does not need to be continuously changed as in the axial flow turbines as well as the flow axis. Therefore, they are advantageous over the axial flow turbines in this respect. However, it is very difficult to predict the design rules and hydrodynamic behavior of such turbines. On the other hand, the flow structure in cross flow turbines introduces varying loads on the aerofoils. In these turbines, the turbine is exposed to variable loads at each rotation, which causes material fatigue. The severity of these mechanical loads determines the turbine lifetime. Therefore, material fatigue analysis is very important in these types of turbines. 
When designing the turbine in cross flow turbines, factors such as limiting the fatigue effects of the material and decreasing the maximum and mean load difference need to be considered.
Generally speaking, cross-flow turbines have two important advantages over axial flow turbines: 1- They can be connected directly to the generator (without using intermediate gear mechanism), 2- They can be easily installed. On the other hand, the hydrodynamics of cross-flow turbines are very difficult due to three different conditions that cause uncertainty, complex turbulence and flow separation. 1 - Ever differing angle of attack. 2- Influence of aerofoil turbulences on each other, 3- Influence of connecting rods on flow. 
In cross-flow turbines, at low rotational speed, changes in angle of attack very effectively influences turbine performance and causes static and dynamic stalls to occur. On the other hand, the performance of the turbine at high speeds is influenced by the turbulence of the flow running into the turbine, the vortices created by the aerofoils and the interactions they have on each other. In addition, as the rotational speed increases, the drag effect of the connecting rods increases and the total generated moment decreases.
In this study, it is planned to use a cross flow turbine in design because, it is more suitable for the system considered, it is simpler and longer lasting for mass production in the future, the system does not need a very high moment generation and low pressure loss is more important in this system.
In this study, three different types of cross flow turbines were numerically compared to each other and the most suitable type of turbine was selected for the turbo solenoid system. 1) Darrieus Turbine, 2) Gorlov Turbine 3) Lucid® Turbine (Figure 1).  The numerical study was based on Sliding Mesh approach where the interaction of eddies shed by blades with consequent blades was taken into account.  
In the CFD analysis except turbine type also the effect of the twisting angle and aerofoil profile on the turbine performance was investigated. As a result of analysis on same dimension turbines with NACA0018 profile, it is understood that Lucid® turbine produce highest torque value and also cause highest pressure drop in pipe.  On the other hand, 10° twisted Gorlov turbine produce 31.3% torque less than Lucid® turbine but against that it is cause 51.4% less pressure drops. 
On the investigation on aerofoil effect Darrieus turbines with NACA0021 and NACA0015 has been studied. As a result of this comparison it is understood that NACA0021 produce 1.5% torque less than NACA0018 but cause 3.3% more pressure drop, and NACA0015 produce 9% higher torque than NACA0018 but cause 1.4% more pressure drop.  
On the investigation on blade twisting angle effect 20° twisted Gorlov turbine has been studied. As a result, it is understood that 20° twisted Gorlov turbine produce 19.1% higher torque and 5.5% less pressure drops than 10° twisted Gorlov turbine. 
In the next step 20° twisted Gorlov turbine with NACA0015 aerofoil has been studied and it is understood that only by 4.7% less torque production and 49.3% less pressure drop, related to Lucid® turbine, 20° twisted Gorlov turbine with NACA0015 aerofoil shows the best result related to all studied turbines. 
For the experimental studies, a 20° twisted Gorlov turbine with NACA0015 aerofoil profile was produced. In addition, a turbine housing was built for a special pipe made from a DN50 size plexiglass material. 
For the experimental studies, a special test setup was used in the SMS-TORK mechanical laboratory. This test setup is a specially designed test rig to measure the performance of solenoid valves. In this test setup, one frequency modulated pump, flowmeter and pressure transmitter are used to calculate the flow coefficient of the valves in the size range from 1/8" to 2".
The pump frequency was set above 42.2 Hz to obtain a flow speed of 3 m/s in the CFD analysis. In this case, the flow meter reads 21.2 m^3/h flow rate. This value means an average flow speed of 3 m/s in a DN50 pipe. 
In the first stage, the turbine is rotating at 141 rad/s with no generator connection and the turbine is neutral. Since the CFD analyses are performed at 157 rad/s, which is greater than 141 rad/s, this time the CFD analyses were repeated with 78.5 rad/s for the Gorlov turbine with a 20° twisted NACA0015 wing profile in order to make an accurate comparison between experimental and numerical analyses. In this case, the average moment value is 0.0176 Nm and the mean pressure loss is calculated as 6.3 kPa. After this step, a special test setup for moment measurement was developed. This system consists of a braking system, a torque meter and a tachometer. 
When the turbine rotates under the effect of 3 m/s flow, the rotation speed is fixed at 78.5 rad/s by means of the brake provided in the system. In these conditions, the moment value is measured as 0.016 Nm. In this case, a difference of 10% is seen between the numerical and experimental result, which is caused by the friction in the bearing and sealing elements. 
On the other hand, a pressure loss of 28.3 kPa was measured in experimental studies with a calibration uncertainty of ±3.5% and equipment accuracy of 0.2%. This value was predicted as 6.3 kPa in the CFD studies. This difference is due to local losses in pipes which was not taken in account in CFD runs. When the turbine is taken off the line, the pressure loss of the pipe is measured as 20.1 kPa. In this case, the pressure loss due to turbine is calculated as 8.2 kPa. This difference between the CFD and the experimental studies is thought to be caused by surface and windage friction on the turbine.