6th International Symposium on the Fusion of Science and Technologies (ISFT2017) Jeju, S. KOREA 17th ~ 21st July, 2017 AN EXPERIMENT ON PERFPRMANCE COMPARISON OF TWO-TYPE TESLA TURBINES APPLICATION IN ORGANIC RANKINE CYCLE Kosart Thawichsri1)*, Wanich nilnont2), Sasikan Phantalad3), and Thanakarn Niamrat4) 1)*,3),4) Energy Engineering Department, Siam Technology College, Bangkok, Thailand. 2) Rajamangala University of Technology Suvarnabhumi, Nonthaburi, Thailand. 1)* Email: kosartpikpik@yahoo.com.sg ABSTRACT: This paper aims to study and design of Organic Rankine Cycle (ORC) using Isopentane as working fluid expanding through Tesla turbine. The study on ORC machine expanding through Tesla turbine has result on the efficiency of Tesla turbine. In addition, Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed. By using an inexpensive experiment device and a simple method, the angular acceleration method, for measuring output torque and power in a Tesla turbine is able to predict a tendency of output work. The experiments using two-types Tesla turbine types, the first type is smooth disks, the second type is added small blades one. In comparison with the second type, it can produce power output more than 60% of the first type. Further study on the machine can be developed throughout the county due to its low cost and efficiency. Keywords: Organic Rankine Cycle, Tesla turbine, high angular speed, inexpensive 1. INTRODUCTION Authors are fully responsible for their papers, which should not have been published elsewhere. They must have taken necessary steps to obtain permission for using any material that might be protected by copyright. Due to the energy crisis, solar energy is developed to generate electricity as one of an alternative energy.[1,2] The use of organic Rankine cycle with thermal energy storage system to produce electricity will decrease the expense on conventional oil because of its low cost and efficiency. Thus, the design and test of Organic Rankine Cycle with thermal powerplants using tesla turbine expander [3] can save much more cost and its source is derived from within country. The Organic Rankine Cycle (ORC) is Rankine cycle with organic working fluid that has boiling point below water boiling point and it works in lowtemperature sources between 80-120 °C. It is produced from various natural and renewable sources such as geothermal energy, waste heat, solar-thermal energy etc. to generate electricity. The Organic Rankine Cycle consists of solar collector, thermal energy storage system and organic Rankine cycle power system with Isopentane [4] as working fluid and turbine expander for shaft work. In paper of Design of Tesla Turbine [5] reference to the change in speed the mechanism becomes very flexible [6]. Mr. Tesla claimed that the total effectiveness of his turbine could reach up to 98% [7]. Professor Warner Rice tried to renew Tesla’s experiments. He used pressure air as a work substance. He reached a total effectiveness between 36% and 41% through his experiment [7]. Professor Rice published a mimeographed named “Tesla Turbomachinery” in 1990 [7], where he specified that by using analytic results the effectiveness of the rotor could be very high (up to 95%) with the effect of laminar flow [7]. The most important parameters that affect the performance and efficiency of disc turbomachinery,[5] as outlined by Cairns [6] and Rice [7], are as follows: (a) spacing between the discs; (b) characteristics of the fluid and the flow, such as velocity ratio; (c) conditions of the surfaces of the disc and radius ratio; (d) radial and axial clearances between the rotor and the housing. 2. THEORY 2.1 Determination of power from torque and angular speed [5] Apart from the direct measurement of power, it can also be calculated from equation (1) once the torque and angular velocity are known P=tw (1) In the following, a method for determining angular speed and several methods for determining the output torques that have been used in the present investigation are described. 2.2 Calculation Procedures [5] A steady, adiabatic, compressible, quasi-onedimensional flow of a perfect gas is assumed. 2.2.1 Inlet: mass flow and power input The mass flow was estimated by means of the 6th International Symposium on the Fusion of Science and Technologies (ISFT2017) Jeju, S. KOREA 17th ~ 21st July, 2017 total and static pressures and total temperature readings at the inlet duct before the turbine. The Pitot tube at that position brings the fluid to rest, making it possible to obtain the total pressure. This process is considered adiabatic and reversible [8], i.e. isentropic. Then, knowing the static-to-stagnation pressure ratio and the stagnation temperature, the velocity of the fluid can be calculated. From the steady flow energy equation it is obtained as æ g -1 2 ö T0 = T ç1 + M ÷ 2 è ø (2) Since the process is assumed to be isentropic, the Mach number and the velocity of the fluid at the point where pressures and temperatures are being measured are respectively M= (g -1) / g ) ù 2 éæ p 0 ö - 1ú = f ( p0 , p ) êçç ÷÷ g - 1 êëè p ø úû (3) and é æ pö V = 2c pT0 ê1 - çç ÷÷ êë è p0 ø ( g -1) / g ) ù ú = f ( p0 , p,T0 ) úû p VA = f ( p0 , p,T0 ) RT (5) With regard to the power input provided by the fluid, it can be defined [9] as (6) Pinput=Q.p01 Q being the volume flowrate calculated with the parameters measured at the inlet duct and p01 the total pressure obtained there. 2.2.2 The turbine as a whole: power and efficiency The ideal power that should be developed by the turbine (isentropic power) is ̇ isen= ̇ cP(T01- W& T -T hen,isen = & en = 01 03 Wisen T01 - T '03 hW,isen = tw m& c p (T01 - T '03 ) hW ,stream = tw Qp01 (1-g ) / g æp ö = T02 çç 02 ÷÷ è p03 ø The actual heat transfer may be computes by calculating either the energy lost by hot fluid or the energy or the cold fluid, as show in equation (13). [10], [11] qH = ̇ CP(Tin-Tout) (13) Rankine Cycle: The iedeal Cycle for vapor power cycle Many of the impracticalities associated with the Carnot cycle can be eliminated by superheating the steam in the boiler and condensing it completely in the condenser, as shown schematically on a T-s diagram and a P-h diagram in Fig.1. The cycle that results is the Rankine cycle, which is the ideal cycle for vapor power plants. The ideal Rankine cycle does not involve any internal irreversibilities and consists of the following four processes: [10] (1-g ) / g (8) The output power due to the actual enthalpy drop is ̇ en= ̇ cP(T01- T03) (9) (12) 2.3 Energy Aanlysis where the ideal outlet temperature can be calculated by analysing the isentropic expansion in the rotor æ p ö T '03 = T02 çç 02 ÷÷ è p'03 ø (11) A third way to define the efficiency of the Tesla disc turbine is as the ratio of the actual power obtained by means of the angular acceleration method and the power of the input stream (equation (6)) (7) ) (10) Moreover, the efficiency can also be defined as the ratio of the actual power obtained by means of the angular acceleration method and the power involved in the corresponding isentropic process (4) Finally, the mass flow can be obtained by introducing the equation of state of a perfect gas and equation (4) in the continuity equation for a one-dimensional steady flow & = rVA = m And then, the efficiency of the turbine defined as the ratio of the output power due to the enthalpy drop and the power involved in the corresponding isentropic process is Fig. 1 P-h diagram of the Rakine cycle. 1-2 Isentropic compression in a pump 6th International Symposium on the Fusion of Science and Technologies (ISFT2017) Jeju, S. KOREA 17th ~ 21st July, 2017 2-3 Constant pressure heat addition in a boiler 3-4Isentropic expansion in a turbine 4-1Constant pressure heat rejection in a condenser Energy Analysis of the Ideal Rankine Cycle All four components associated with the Rankine cycle (the pump, boiler, turbine, and condenser) are steady-flow devices, and thus all four processes that make up the Rankine cycle can be analyzed as steadyflow processes. The kinetic and potential energy changes of the steam are usually small relative to the work and heat transfer terms and are therefore usually neglected [10]. Then the steady-flow energy equation per unit mass of steam reduces to (14) Rankine Cycle”[12] Organic Rankine Cycle (ORC) Machine using Isopentane as working fluid expanding through turbine. Theory for calculate, Organic Rankine Cycle, using heat source at temperatures 90, 80 and 70 °C respectively, calculating by approximately from the experiment and comparison with P-h and T-s Diagram of a working fluid. The experiments using two-types Tesla turbine types, the first type is smooth disks, the second type is added small blades one. 3.1 Experiment Methods (the first type is smooth disks) (14) 1. The turbine is assumed to be isentropic. Then the conservation of energy relation for device can be expressed as follow: 2. (15) 4. 5. (qin-qout)+(Win-Wout)=he-hin) Wturbine,out= h3-h4 3. EQUIPMENT AND DATA COLLECTING POSITION. 3. Preparing the water in a hot water storage tank at temperature 90 °C. Open water valve the hot water storage tank sends the hot water flows to reach inside boiler. Open working fluid valve expanded through Tesla Turbine (smooth disks) Recording data saving follow all position. Starting step 1 to 4 again by change temperatures in the hot water storage tank at temperature 90, 80 and 70 °C respectively. Correct data savings many time, for the data that is correct most accurate. 3.2 Experiment Methods (the second type is added small blades one) 1. 2. 3. Fig. 2The diagram of Organic Rankine Cycle system and data collecting position. 4. 5. Preparing the water in a hot water storage tank at temperature 90 °C. Open water valve the hot water storage tank sends the hot water flows to reach inside boiler. Open working fluid valve expanded through Tesla Turbine (added small blades one) Recording data saving follow all position. Starting step 1 to 4 again by change temperatures in the hot water storage tank at temperature 90, 80 and 70 °C respectively. Correct data savings many time, for the data that is correct most accurate. Fig. 3 Tasla turbine plate of the first type. Fig. 5 comparison of two-type Turbines. 4. RESULT S AND DISCUSSION. Fig. 4 Tasla turbine plate of the Second type. From the paper “A study and design of Organic Calculation theory of Organic Rankine Cycle, using heat source at temperatures 90 °C which calculating by approximately from the experiment and comparison with P-h and T-s Diagram of a working fluid using heat source at temperatures 90 °C, result the working fluid through Turbine at pressure and temperature inlet state 6 bar and 80 C respectively, at 6th International Symposium on the Fusion of Science and Technologies (ISFT2017) Jeju, S. KOREA 17th ~ 21st July, 2017 pressure and temperature outlet state 1 bar and 30 °C respectively, output power 50 kJ/kg. The experiments using two-types Tesla turbine types, the first type is smooth disks, the second type is added small blades one. In comparison with the second type, it can produce power output more than 60% of the first type. The first type, an evaluation on Organic Rankine Cycle systerm, output power 50 kJ/kg, mass flowrate of working fluid 0.05 kg/s through Turbine claimed that the total effectiveness 36%, speed 3,000 r/min, we can calculate Torque equal 18 N.m. The use of heat source at temperatures 80 and 70 °C, result output power 35 and 20 kJ/kg, respectively, mass flow rate of working fluid 0.05 kg/s through Turbine claimed that the total effectiveness 36%, speed 3,000 r/min we can calculate Torque equal 12.6 and 7.2 N.m., respectively. The second type, an evaluation on Organic Rankine Cycle system, output power 50 kJ/kg, mass flowrate of working fluid 0.05 kg/s through Turbine claimed that the total effectiveness 5 7.6 %, speed 3,000 r/min, we can calculate Torque equal 28.8 N.m. The use of heat source at temperatures 80 and 70 °C, result output power 20.2 and 11.5 kJ/kg, respectively. acceleration method, for measuring output torque and power in a Tesla turbine which experiment device must inexpensive but its can explain tendency for output work. Further study on the machine can be developed throughout the county due to its low cost and efficiency. 5. CONCLUSION Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed The experiments using two-types Tesla turbine types, the first type is smooth disks, the second type is added small blades one. In comparison with the second type, it can produce power output more than 60% of the first type. An evaluation on Organic Rankine Cycle systerm using heat source at temperatures 90, 80 and 70 °C, result the output power 50, 35 and 20 kJ/kg, respectively, mass flowrate of working fluid 0.05 kg/s through the first type Turbine claimed that the total effectiveness 36%, speed 3,000 r/min, we can calculate Torque equal 18, 12.6 and 7.2 N.m. respectively, and the second type , we can calculate Torque equal 28.8, 20.2 and 11.5 N.m., respectively. A Tesla turbine which experiment device must inexpensive but its can explain tendency for output work. Further study on the machine can be developed throughout the county due to its low cost and efficiency NOMENCLATURE Fig. 6 Result of comparison of two-size Tesla Turbines. The study reveals that low-temperature sources had low power output also. If we use low-temperature sources for suitable, it will get better development. The most important parameters that affect the performance and efficiency of disc turbomachinery are as follows: - spacing between the discs. characteristics of the fluid and the flow, such as velocity ratio. conditions of the surfaces of the disc and radius ratio. radial and axial clearances between the rotor and the housing. In addition, Thermodynamics theory on isentropic efficiency proved to be a successful method for overcoming the difficulties associated with the determination of very low torque at very high angular speed. By using a simple method, the angular qH ̇ Cp Tin Tout h1 h2 h3 h4 cp M p P Q r R T V γ ρ τ ω heat transfer at moment [W] mass flow rate [kg/s] specific heat capacity [kJ/kg K] temperature inlet [K] temperature outlet [K] Specific enthalpy at the inlet state [kJ/kg] Specific enthalpy at the exit state [kJ/kg] Specific enthalpy at the inlet state [kJ/kg] Specific enthalpy at the inlet state [kJ/kg] specific heat capacity at constant pressure Mach number pressure power volume flowrate radius of the disc gas constant distance between the centre of th e disc and the centre of the pole temperature absolute velocity ratio of specific heats density torque rotor angular velocity Subscripts 0 stagnation conditions 1 conditions at the inlet of the nozzle 2 conditions outlet of the nozzle/inlet of the rotor 3 conditions at the exhaust from the turbine en power due to enthalpy drop isen power of the isentropic process 6th International Symposium on the Fusion of Science and Technologies (ISFT2017) Jeju, S. KOREA 17th ~ 21st July, 2017 stream power due to the input stream of fluid out put from the angular acceleration method i inner o outer Konference diplomových prací 2007, Ústav konstruování, Ústav mechaniky těles, mechatroniky a biomechaniky, FSI VUT v Brně 5. – 6. června 2007, Brno, Česká republika. Superscript [6] LAIKA, Viktor. Alphabet of small water gears: Tesla turbine [online]. Last revision 1.4.2004 [cit.2007-03-31]. http://mve.energetika.cz/jineturbiny/tesla.htm. ¢ Ideal (isentropic) condition 6. REFERENCES [1] Takashisa Yamamoto, Tomohiko Furuhata, Norio Arai, Koichi Mori, “Design and testing of the Organic Rankine Cycles” Science Direct, Vol ume 26(2001), p. 239-251. [2] Organic Rankine Cycle:From Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Organic_Rankine_Cycle : 4 August 2009. [3] Piotr Lampart, Krzysztof Kosowski, Marian Piwowarski, Łukasz Jędrzejewski, Design analysis of Tesla micro-turbine operating on a low-boiling medium: Special issue 2009/S1; pp. 28-33. [4] Bertrand Fankam Tchanche, George Papadakis, Gregory Lambrinos, Antonios Frangoudakiss “Fluid selection for a low-temperature solar organic Rankine cycle” Applied Thermal Engineering, Volume 29 (2009), p. 2468-2476. [5] David Paloušek, DESIGN OF TESLA TURBINE, [7] Rice, W. Tesla turbomachinery. In Handbook of turbomachinery(Ed. E. Logan), 2003 (Marcel Dekker, New York). [8] Massey,B.Mechanics of fluids, 8th edition, 2006 (Taylor&Francis, Oxon). [9] Roddy, P. J., Darby, R., Morrison, G. L., and Jenkins, P. E. Performance characteristics of a multipledisk centrifugal pump. J. Fluids Eng., 1987, 109, 51–57. [10] Cengel, Y. A., 1998, Thermodynamics, 3rd ed, New York: McGraw-Hill. Mar. 2012. [11] Holman, J.P., 2001, Heat Transfer, 8th ed, Singapore: McGraw-Hill. [12] Thawichsri, V. Monyakul, S. Thepa, C. Jivacate and K. Sudaprasert, A study and design of Organic Rankine Cycle Machine, GMSARN International Conference on Social-Energy-Environmental Development: SEED towards Sustainability 28-30.