SERBEST DİSPLEYSIRLI BİR STİRLİNG MOTORUNUN NODAL TERMODİNAMİK VE DİNAMİK ANALİZİ

Year 2021, Volume: 41 Issue: 1, 141 - 155, 30.04.2021

Can Cınar Onur Ozdemır Halit Karabulut Mesut Duzgun

https://doi.org/10.47480/isibted.979390

Cited By: 2

Abstract

Bu çalışmada, serbest displeysırlı Stirling motorlarının dinamik ve termodinamik özellikleri bir simülasyon programı hazırlanarak incelenmiştir. Simülasyon programının dinamik kısmı, güç pistonu, krank mili ve displeysırın hareket denklemlerini içermektedir. Termodinamik kısmında da 24 nodal hacme dayanan bir nodal analiz yapılmıştır. Çalışmada, bu motorları ilk harekete geçirmek için, displeysırın doğal frekansı olarak bir başlangıç hızı gerektiği görülmektedir. Motor çalışırken displeysır vuru olarak adlandırılan bazı ikincil titreşimler sergilemekte, bu durum iş ve güç üretiminde düzensizliklere sebep olmaktadır. Bu durum, displeysır kütlesi, çalışma maddesi kütlesi, harici yük ve yay sabiti gibi bazı çalışma parametreleri değiştirilerek en aza indirilebilir. Çalışma maddesi şarj basıncının her bir değeri için farklı bir yaya ihtiyaç duyulmaktadır. Aynı yay sabiti değeri için, displeysır kütlesi sınırlı bir aralıkta değiştirilebilmektedir. Displeysır kütlesi azalırken motorun termal performansı artmaktadır. 1000 K sıcak uç sıcaklığı ve 356 K soğuk uç sıcaklığı arasında ve 18 bar şarj basıncında çalışan bir motor için efektif termik verim %21-26 arasındadır. 3,5 litre toplam iç hacme sahip bir motor, 3,9 kW efektif güç ve 4,7 kW indike güç üretebilmektedir. Motor performansı ile faz açısı arasında güçlü bir ilişki olduğu görülmektedir.

Keywords

Serbest displeysır, Stirling motoru, Dinamik ve termodinamik simülasyon, Performans tahmini, Displeysır kütlesinin optimizasyonu, Yay sabitinin optimizasyonu

NODAL THERMODYNAMIC AND DYNAMIC ANALYSIS OF A FREE DISPLACER STIRLING ENGINE

Abstract

In this study, the dynamic and thermodynamic features of free displacer Stirling engines were investigated by preparing a simulation program. The dynamic component of the simulation program involves the movement equations of power piston, crankshaft and displacer. The thermodynamic component is a nodal analysis based on 24 nodal volumes. The study indicates that starting these engines requires an initial speed is required as the displacer system natural frequency. While the engine is running, the displacer exhibits some secondary vibrations (named as beatings) and causes irregularities in its work and power generation however, it can be minimized by changing some working parameters such as displacer mass, working fluid mass, external loading, spring constant etc. For each value of the working fluid charging pressure, a different spring is needed. While the spring constant is the same, the displacer mass can vary in a limited range. The thermal performance of the engine increases as the displacer mass is decreasing. For an engine working between 1000 K heater temperature, 356 K cooler temperature and 18 bar charging pressure, the effective thermal efficiency ranges between 21 and 26 %. An engine with a 3.5 liter total inner volume is capable of generating about 3.9 kW effective power and 4.7 kW indicated power. A strong relation is observed between engine performance and phase angle.

Keywords

Dynamic and thermodynamic simulation, Free displacer Stirling engine, Performance prediction, Optimization of displacer mass, Optimization of spring constant

References

• Abbas M, Boumeddane B, Said N, Chikouche A. Dish Stirling technology: A 100 MW solar power plant using hydrogen for Algeria. International Journal of Hydrogen Energy, 2011;36:4305-4314. doi.org/10.1016/j.ijhydene.2010.12.114.
• Altin M, Okur M, Ipci D, Halis S, Karabulut H. Thermodynamic and dynamic analysis of an alpha type Stirling engine with Scotch Yoke mechanism. Energy, 2018;148:855-865. doi:10.1016/j.energy.2018.01.183
• Begot S, Layes G, Lanzetta F, Nika P. Stability analysis of a free piston Stirling engines. The European Physical Journal Applied Physics, 2013;61:30901. doi:10.1051/epjap/2013120217.
• Cheng CH, Yang HS, Jhou BY, Chen YC, Wang YJ. Dynamic simulation of thermal-lag Stirling engines. Applied Energy, 2013;108:466-476. doi: 10.1016/j.apenergy.2013.03.062.
• Chi C, Moua J, Lina M, Honga G. CFD simulation and investigation on the operating mechanism of a beta-type free piston Stirling engine. Applied Thermal Engineering, 2020;166:114751. doi: 10.1016/j.applthermaleng.2019.114751.
• De la Bat BJG, Dobson RT, Harms TM, Bell AJ. Simulation, manufacture and experimental validation of a novel single acting free-piston Stirling engine electric generator. Applied Energy, 2020;263:114585. doi:10.1016/j.apenergy.2020.114585.
• Formosa F. Coupled thermodynamic-dynamic semi-analytical model of free piston Stirling engines. Energy Conversion and Management, 2011;52:2098-2109. doi:10.1016/j.enconman.2010.12.014.
• Karabulut H. Dynamic analysis of a free piston Stirling engine working with closed and open thermodynamic cycles. Renewable Energy, 2011;36:1704-1709. doi:10.1016/j.renene.2010.12.006.
• Karabulut H, Cinar C, Okur M. Dynamic simulation and performance prediction of free displacer Stirling engines. International Journal of Green Energy, 2020;17(7):427-439. doi:10.1080/15435075.2020.1761814.
• Karabulut H, Okur M, Ozdemir AO. Performance prediction of a Martini type of Stirling engine. Energy Conversion and Management, 2019;179:1-12. doi:10.1016/j.enconman. 2018.10.059.
• Kwankaomeng S, Silpsakoolsook B, Savangvong P. Investigation on stability and performance of a free-piston Stirling engine. Energy Procedia, 2014;52:598-609. doi:10.1016/j.egypro.2014.07.115.
• Lin M, Mou J, Chi C, Hong G, Ge P, Hu G. A space power system of free piston Stirling generator based on potassium heat pipe. Frontiers in Energy, 2020;14(1):1-10. doi:10.1007/s11708-019-0655-6.
• Majidniya M, Boileau T, Remy B, Zandi M. Nonlinear modeling of a free piston Stirling engine combined with a permanent magnet linear synchronous machine. Applied Thermal Engineering, 2020;165:114544. doi:10.1016/j.applthermaleng.2019.114544.
• Masoumi AP, Tavakolpour-Saleh AR. Experimental assessment of damping and heat transfer coefficients in an active free piston Stirling engine using genetic algorithm. Energy, 2020;195:117064. doi:10.1016/j.energy.2020.117064.
• Mehdizadeh NS, Stouffs P. Simulation of a Martini displacer free piston Stirling engine for electric power generation. International Journal of Applied Thermodynamics, 2000;3(1):27-34. doi:10.5541/ijot.30.
• Mou J, Hong GA. A numerical model on thermodynamic analysis of free piston Stirling engines. IOP Conference Series: Materials Science and Engineering, 2017;171:012090. doi:10.1088/1757-899X/171/1/012090.
• Park J, Ko J, Kim H, Hong Y, Yeom H, Park S, In S. The design and testing of a kW-class free-piston Stirling engine for micro-combined heat and power applications. Applied Thermal Engineering, 2020;164:114504. doi:10.1016/j.applthermaleng.2019.114504.
• Tanaka M, Yamashita I, Chisaka F. Flow and heat transfer characteristics of the Stirling engine regenerator in an oscillating flow. JSME International Journal, 1990;33(2):283-289. doi:10.1299/jsmeb1988.33.2_283.
• Tavakolpour-Saleh AR. Zare SH, Bahreman H. A novel active free piston Stirling engine: modeling, development, and experiment. Applied Energy, 2017;199:400-415. doi:10.1016/j.apenergy.2017.05.059.
• Wood JG, Lane N. Advanced 35 W free-piston Stirling engine for space power applications. AIP Conference Proceedings 2003;654:662-667. doi:10.1063/1.1541353.
• Ye W, Yang P, Liu Y. Multi-objective thermodynamic optimization of a free piston Stirling engine using response surface methodology. Energy Conversion and Management, 2018;176:147-163. doi:10.1016/j.enconman.2018.09.011.
• Zare S, Tavakolpour-Saleh AR. Predicting onset conditions of free piston Stirling engine. Applied Energy 2020;262:114488. doi:10.1016/j.apenergy.2019.114488.
• Zare S, Tavakolpour-Saleh AR, Sangdani MH. Investigating limit cycle in a free piston Stirling engine using describing function technique and genetic algorithm. Energy Conversion and Management, 2020;210:112706. doi:10.1016/j.enconman.2020.112706.
• Zhou Q, Xia Y, Liu G, Ouyang X. A miniature integrated nuclear reactor design with gravity independent autonomous circulation. Nuclear Engineering and Design, 2018;340:9-16. doi:10.1016/j.nucengdes.2018.09.013.
• Zhu S, Yu G, Ma Y, Cheng Y, Wang Y, Yu S, Wu Z, Dai W, Luo E. A free-piston Stirling generator integrated with a parabolic trough collector for thermal-to-electric conversion of solar energy. Applied Energy, 2019;242:1248-1258. doi:10.1016/j.apenergy.2019.03.169.