Study on a high efficiency thermoacoustic engine

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International Workshop on Construction of Low-Carbon Society Using Superconducting and Cryogenics Technology (March 7-9, 2016) Study on a high efficiency thermoacoustic engine Shinya Hasegawa Hideki

1 International Workshop on Construction of Low-Carbon Society Using Superconducting and Cryogenics Technology (March 7-9, 2016) Study on a high efficiency thermoacoustic engine Shinya Hasegawa Hideki Kimura Kota Fukuda Shun Takahashi Kazuto Kuzuu E. M. Sharify (Presenter) Mariko Senga Tokai University ( Dep. of Prime Mover Engineering ) ( Dep. of Electrical & Electronic Eng. ) ( Dep. of Aeronautic & Astronautics ) ( Dep. of Prime Mover Engineering ) ( Dep. of Prime Mover Engineering ) ( Dep. of Prime Mover Engineering ) ( Graduate School of Engineering )

2 Introduction The thermoacoustic engine (TE) is an energy-conversion device which converts heat and acoustic power and has no moving parts! Thermoacoustic engine with high efficiency was first realized in (SWIFT, NATURE, 1999) Power generation Power Heat source Acoustic wave + ー 2

3 Introduction Maintenance-free: absence of moving parts and simplicity of the components High efficiency: changes the heat flow to the acoustic power based on the Carnot cycle. Low-cost structure: extremely simple structure that works through the pipe and does not require special parts. 3

比カルノー効率 [%] Introduction High efficiency at low temperature: Regenerator with high thermal efficiency could be obtained when : 100 80 I.

4 比カルノー効率 [%] Introduction High efficiency at low temperature: Regenerator with high thermal efficiency could be obtained when : I. the phase difference between the pressure and the mean velocity is close to zero. II. III. hydraulic radius much less than thermal penetration depth to reduce viscous losses in the regenerators, z value be sufficiently large ωτ z/ρ m c 30 Multiple heat sources: Generally in the factory the waste heat is generated in different location rather than one place. While, the waste heat device can recover heat from single location of the heat source. 4

5 Acoustic Power Introduction To overcome this problem : I. Low temperature operating TA engine with high efficiency: Using multistage thermoacoustic engines with high acoustic impedance that operate by multiple heat sources is used. II. III. Reducing the non-linear effects: Using PIV, LIF and numerical methods to suppress the minor loss and mass flow. Compact, high-output linear generator: Local high acoustic impedance Compact Highoutput linear generator ハイスピード YLF レーザ KANOMAX DYLF-L300 デジタルハイスピードカメラ KANOMAX HSS-7 Reducing the non-linear effects 5

6 Introduction To overcome this problem : I. Low temperature operating TA engine with high efficiency: II. Reducing the non-linear effects: III. Compact, high-output linear generator: In order to evaluate the TE more quantitatively. Total heat Q in0 = Q prog + Q stand +Q D +Q κ Thermal efficiency of oscillating flow W η = Q prog + Q stand +Q D 6

The cascade thermoacoustic engine 音響パワー By controlling the acoustic field, high local acoustic impedance in regenerator area are achieved, which was more than 5 times of the acoustic impedance of the

7 The cascade thermoacoustic engine 音響パワー By controlling the acoustic field, high local acoustic impedance in regenerator area are achieved, which was more than 5 times of the acoustic impedance of the acoustic waves propagating in outside of regenerator area. 1 Local high acoustic Imp. The energy conversion with high efficiency is realized by using multiple regenerators with high acoustic impedance. 7

The cascade thermoacoustic engine The acoustic power increase as the absolute temperature ratio T H /T R increase: T H Wout Win P. H. Ceperley, J. Acoust. Soc. Am., 66, 1508-1513, 1979.

8 The cascade thermoacoustic engine The acoustic power increase as the absolute temperature ratio T H /T R increase: T H Wout Win P. H. Ceperley, J. Acoust. Soc. Am., 66, , TC By using multiple regenerator : W out W in T T H C n Therefore, it is possible to increase the power gain for a low temperature ratio as well. T. Biwa et.al., J. Acoust. Soc. Am., 129, ,

9 The cascade thermoacoustic engine The engine unit JTEKT PD104K FOSTEX FW108N Waveguide (φ14) Flow channel diameter : 0.48mm, 30mm 9

temperature of the cold and hot heat exchangers were around

10 The high efficiency thermoacoustic engine Acoustic power More than 50% of the Carnot efficiency achieved when the temperature of the cold and hot heat exchangers were around 300K and 600K, respectively. More than 50% of the Carnot efficiency 10

11 The high efficiency thermoacoustic engine In 1979, Ceperley proposed a traveling-wave thermoacoustic engine in which the acoustic power was amplified by traveling-wave propagation through a differentially heated regenerators *P. H. Ceperley, J. Acoust. Soc. Am., 66, ,(1979). In 1985, Ceperley realized the relationship between the specific acoustic impedance z (= p / u) and thermal efficiency Acoustic impedance z=10ρ m c Specific Carnot efficiency η 2 =79% *P. H. Ceperley, Gain and efficiency of a short traveling wave heat engine, J. Acoust. Soc. Am. 77 (3), (1985). 11

12 The high efficiency thermoacoustic engine In 1999, Backhaus built a quarter-wavelength mode prototype traveling-wave thermoacoustic engine and introduced a resonator in a looped tube and with high acoustic impedance ( z=30 ρ m c) in the regenerator area, they achieved 42% of the Carnot eff. Following the concept of Backhaus and Swift et al, Tijani built thermal efficiency with 49% of the Carnot efficiency in S. Backhaus and G. W. Swift, A thermoacoustic stirling engine, Nature (London) 399, (1999). However, due to the lack of the boundary condition, it is difficult to install the regenerator at exactly peak acoustic impedance for a quarter-wavelength mode. Reduction in the efficiency 12

13 The high efficiency thermoacoustic engine By the driver, the acoustic field at the regenerator area are controlled. 6.01m Unit Linear motor :Pressure transducers Ambient HX Hot HX HX:Heat exchangers Regenerator Linear motor Power amplifier Function generator Installing linear motor on the left and right side and controlling the phase and amplitude by function generator, the specific acoustic impedance can be changed at the end of the unit such as 10ρ m c,5ρ m c,2ρ m c,1ρ m c. Operating frequency: 35Hz Working gas: helium 10 atm TH: 300 TC: 20 The zero phase difference between pressure and velocity amplitude at downstream part 20 W acoustic power at downstream part. 13

14 The high efficiency thermoacoustic engine Heat exchanger (Tapered fin) Plate thickness : 1.0mm gap between each plate:2.0 mm Materials: Etched stainless steel mesh length :30mm diameter :40mm Flow channel :0.3mm ωτ: porosity :77.85% 14

The thermoacoustic electrical generator Through analysis of dynamic magnetic field,

electric power, new linear generator is required which is capable of switching

15 The thermoacoustic electrical generator Through analysis of dynamic magnetic field, the prototype of linear power generator is designed which generates the output power of 200W with 80% eff. To convert high frequency (50-200) acoustic power with small strokes into the electric power, new linear generator is required which is capable of switching rapidly between the magnetic poles of the generator. Coil Outer yoke (axis) Outer yoke (cover) Mover Permanent magnet Compacted and High-output linear generator 15

Wu 64Hz => 1043W Z. Wu, L. Zhang, W. Dai and E.

16 The thermoacoustic electrical generator Moving-coil linear generator 2004,S. Backhaus 120Hz => 58W S. Backhaus, E. Tward and M. Petach: Applied Physics. Lett., 85, pp (2004). Moving-magnet type linear generator 2014,Z. Wu 64Hz => 1043W Z. Wu, L. Zhang, W. Dai and E. Luo: Investigation on a 1 kw travelingwave thermoacoustic electrical generator, Applied Energy, 124, pp (2014). Moving-coil type Moving-magnet type Low output High 16 light the mover Heavy 16

17 Energy flow around the engine core plates To construct the optimized regenerator and exchangers, it is essential to realize the energy flow around the regenerator and heat exchanges. PIV, LIF, and CFD are the basic tools. 17

18 Energy flow around the engine core plates Work Flow Heat Flow Enthalpy Flow Q = T m s=aρ m T m S u t r I = A P u r t H = Q+I = Aρ m C p T u t r The enthalpy flow can be driven from the temperature and velocity. 18

19 Energy flow around the engine core plates Measuring velocity amplitude (u) Measuring Temperature variation (T) PIV (particle image velocimetry) LIF(Laser-induced fluorescence) The enthalpy flow in the core can be measured 19

Energy flow around the engine core plates Loud Speaker X=0 1.815 m 1.77 m 3.

Controller PIV High speed Camera Measuring oscillatory flow in the vicinity

20 Energy flow around the engine core plates Loud Speaker X= m 1.77 m 3.71 m 45mm 3mm 4mm 45mm PIV YAG Laser Power Amplifier Function Generator PIV Controller PIV High speed Camera Measuring oscillatory flow in the vicinity of a parallel plates placed in a traveling-wave thermoacoustic using the PIV 20

21 Energy flow around the engine core plates Measurement of velocity amplitude distribution by PIV PIV analysis Measuring the velocity distribution in the parallel plate 21

22 Energy flow around the engine core plates Comparison of the PIV and analytical results velocity amplitude distribution in the parallel plate Comparison of experimental and analytical results Future Plan: measuring the temperature and enthalpy flow by LIF 22

23 Governing equations were two-dimensional compressible Navier-Stokes equations: y F x E y F x E t Q v v y yy yx yy yx v x xy xx xy xx u T v u F T v u E v p e p v vu v F u p e uv p u u E e v u Q 0, 0, ) (, ) (, 2 2 The pressure p is related to the total energy e per unit mass by the equation of state: v u p e The temperature T in the energy equation was estimated using the specific heat at constant pressure C p based on the ideal gas law: v u p e T C p 23 Energy flow around the engine core plates

24 Energy flow around the engine core plates Kazuto Kuzuu, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede 24

Energy flow around the engine core plates Temperature field 2 1.

(m/s) F01 F05 0.5 5 0 0 F06 F12-0.5-5 F07 F11-1 -10 F08-1.

25 Energy flow around the engine core plates Temperature field F03 F04 u-velocity observed phase u observed phase disp F02 10 Temperature distribution around the engine HEX REG CEX Uave (m/s) F01 F F06 F F07 F F F10-15 F phase (degrees) Displacement (mm) F=60 degs F=120 degs F=180 degs F=240 degs F=300 degs F=360 degs Kazuto Kuzuu, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede 25

26 Energy flow around the engine core plates Reproduction of a self-sustained oscillation u-velocity pressure u (m/s) P (Pa) time (sec) Time variation of velocity and pressure amplitude Closed end at (x,y) = (1.04,0.0) Open end Kazuto Kuzuu, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede 26

27 Energy flow around the engine core plates Verification of the simulation Phase variation of section average velocity and displacement amplitude at x= F02 F03 F04 u-velocity observed phase u observed phase disp Lines : CFD Symbols : Linear analysis Comparison of velocity profiles Uave (m/s) F01 F F06 F F07 F F F10-15 F Displacement (mm) phase (degrees) y (mm) 0 y (mm) F01 F02 F03 F04 F05 F06 F07 F08 F09 U (m/s) F10 F11 F12 F01 F02 F03 x = m (middle section of REG) Closed end F04 F05 F06 F07 F08 F09 F10 F11 F F01 F02 F03 F04 F05 F06 F07 F08 F09 U (m/s) F10 F11 F12 F01 F02 F03 x = 2.00 m (section of resonance tube) Open end F04 F05 F06 F07 F08 F09 F10 F11 F12 Kazuto Kuzuu, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede 27

Energy flow around the engine core plates i. Pressure: 0.1Mpa ii. iii.

hot heat exchanges are set 300K and 600K, respectively Displacement

length 180mm 67.5mm 15mm 15mm 15mm 67.5mm A.

Schematic of the computation domain 1.5mm 4mm 1.

28 Energy flow around the engine core plates i. Pressure: 0.1Mpa ii. iii. iv. Working Fluid: Air Frequency: Hz The temperatures of cold and hot heat exchanges are set 300K and 600K, respectively Displacement amplitudes : 25%, 50%, 75%, 100%, 125%, and 150% of the regenerator length 180mm 67.5mm 15mm 15mm 15mm 67.5mm A.W Impedance-matching Boundary condition 300K T 300K X 600K 600K Schematic of the computation domain 1.5mm 4mm 1.5mm Impedance-matching Boundary condition E.M. Sharify, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede 28

E.M. Sharify, Shun Takahashi, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics 26-27 Oct.

29 E.M. Sharify, Shun Takahashi, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschede The acoustic load is defined by a linear system consisting of mass, spring and damper components with the periodic input force p =Psin(ωt+φ) and periodic output velocity u =Usin(ωt): Φ U P c Φ U P k m p u dt k cu dt du m cos sin Parameters m, c and k for each system are determined: L L L L L U P c k m 0 F F R R R R R R R R R U P c U P k m cos sin Schematic of the IMB condition 29 Energy flow around the engine core plates

30 Energy flow around the engine core plates 300K T 600K X A. wave 300K 600K Temperature a) Oscillation amp. 50% of the regenerator length (10 Hz) Temperature b) Oscillation amp. 100% of the regenerator length (10 Hz) Temperature c) Oscillation amp. 150% of the regenerator length (10 Hz) E.M. Sharify, Shun Takahashi, Shinya Hasegawa, 3 rd International Workshop on Thermoacoustics Oct Enschde 30

31 Energy flow around the engine core plates 10Hz 30Hz 40Hz 50Hz 31

T. Yazaki Department of Physics, Aichi University, Kariya 448, Japan

T. Yazaki Department of Physics, Aichi University, Kariya 448, Japan Experimental studies of a thermoacoustic Stirling prime mover and its application to a cooler Y. Ueda, a) T. Biwa, and U. Mizutani Department of Crystalline Materials Science, Nagoya University, Nagoya