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Halit Karabulut - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic and dynamic analysis of an alpha type stirling engine and numerical treatment
Energy Conversion and Management, 2018Co-Authors: Duygu Ipci, Halit KarabulutAbstract:Abstract In this study, the nodal thermodynamic and dynamic analysis of an alpha type Stirling engine driven by Scotch-yoke mechanism is presented. The nodal thermodynamic section of the analysis is performed via 15 nodal volumes. The temperature variations in nodal volumes are calculated by means of the first law of the thermodynamics given for the open systems. The Pressures in all of the nodal volumes are assumed to be equal and calculated via Schmidt relation. The momentary masses in nodal volumes are calculated via the perfect gas relation. The dynamic section of the analysis involves the motion equations of pistons and crankshaft. The motion equations are derived by means of the Newton method. In the derivation of the motion equations of pistons, the working fluid forces and friction forces are considered beside the inertia forces. In the derivation of motion equation of the crankshaft, moments of working fluid forces, moments of friction forces, the moment of external load and the moment of starter motor are considered as well as mass inertia moments. It is estimated that an engine having 1.8 L swept volume, 1000 K hot end temperature, 400 K cold end temperature, 3000 cm2 total inner heat transfer area, 5.1 bar Charge Pressure and 2000 W/m2 K inner heat transfer coefficient is capable of producing a shaft power above 2 kW. For these inputs and shaft power; the speed, speed fluctuation and torque are optimized as 138 rad/s, 16% and 14.9 N m respectively. The presented analysis is useful for engine development studies.
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thermal performance of a stirling engine powered by a solar simulator
Applied Thermal Engineering, 2015Co-Authors: Fatih Aksoy, Can Cinar, Hamit Solmaz, Yasar Onder Ozgoren, Halit Karabulut, Ahmet UyumazAbstract:Abstract In this study, the performance of a beta type Stirling engine which works at relatively lower temperatures was investigated using 400 W and 1000 W halogen lamps as a heat source and helium as the working fluid. The working fluid was Charged into the engine block and the Pressure of the working fluid was ranged from 1 to 5 bars with 1 bar increments. The halogen lamps were placed into a cavity adjacent to the hot end of the displacer cylinder, which is made of aluminum alloy. In the experiments conducted with 400 W halogen lamp, the temperature of the cavity was 623 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 37.08 W, 1.68 Nm and 9.27%, at 5 bar Charge Pressure. For the 1000 W halogen lamp, the temperature of the cavity was determined to be 873 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 127.17 W, 3.4 Nm and 12.85%, at the same Charge Pressure. The experimental thermal efficiencies of the engine were also compared with thermodynamic nodal analysis.
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performance comparison of a novel configuration of beta type stirling engines with rhombic drive engine
Energy Conversion and Management, 2014Co-Authors: Hamit Solmaz, Halit KarabulutAbstract:This study presents a beta type Stirling engine mechanism and its performance analysis. The displacer motion of the engine is performed by a lever mechanism. The performance of the engine was investigated via comparing with a rhombic-drive engine possessing an equal sided rhombic. Comparison was made for kinematic behaviors, power and thermal efficiency. For comparison; the piston swept volume, the inner heat transfer area, the hot and cold end temperatures, the inner heat transfer coefficient, Charge Pressure and dead volumes were kept equal for both engines. As working fluid the helium was used. Thermodynamic treatments of engines were performed via the nodal analysis. The power of the lever driven engine was found to be greater than the power of the rhombic drive engine. Under the equal Charge Pressure, the thermal efficiency of the lever driven engine was found to be lower than the efficiency of the rhombic drive engine however, under the equal working fluid mass the thermal efficiency of the lever driven engine was found to be greater than that of the rhombic drive engine. The external volume and mass of the lever driven engine is lower than the rhombic drive engine.
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torque and power characteristics of a helium Charged stirling engine with a lever controlled displacer driving mechanism
Renewable Energy, 2010Co-Authors: Halit Karabulut, Can Cinar, E Ozturk, Huseyin Serdar YucesuAbstract:This study presents test results of a Stirling engine with a lever controlled displacer driving mechanism. Tests were conducted with helium and the working fluid was Charged into the engine block. The engine was loaded by means of a prony type micro dynamometer. The heat was supplied by a liquefied petroleum gas (LPG) burner. The engine started to run at 118°C hot end temperature and the systematic tests of the engine were conducted at 180°C, 220°C and 260°C hot end external surface temperatures. During the test, cold end temperature was kept at 27°C by means of water circulation. Variation of the shaft torque and power with respect to the Charge Pressure and hot end temperature were examined. The maximum torque and power were measured as 3.99Nm and 183W at 4bars Charge Pressure and 260°C hot end temperature. Maximum power corresponded to 600rpm speed.
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an experimental study on the development of a β type stirling engine for low and moderate temperature heat sources
Applied Energy, 2009Co-Authors: Halit Karabulut, Can Cinar, Huseyin Serdar Yucesu, Fatih AksoyAbstract:In this study, a [beta]-type Stirling engine was designed and manufactured which works at relatively lower temperatures. To increase the heat transfer area, the inner surface of the displacer cylinder was augmented by means of growing spanwise slots. To perform a better approach to the theoretical Stirling cycle, the motion of displacer was governed by a lever. The engine block was used as pressurized working fluid reservoir. The escape of working fluid, through the end-pin bearing of crankshaft, was prevented by means of adapting an oil pool around the end-pin. Experimental results presented in this paper were obtained by testing the engine with air as working fluid. The hot end of the displacer cylinder was heated with a LPG flame and kept about 200 °C constant temperature throughout the testing period. The other end of the displacer cylinder was cooled with a water circulation having 27 °C temperature. Starting from ambient Pressure, the engine was tested at several Charge Pressures up to 4.6 bars. Maximum power output was obtained at 2.8 bars Charge Pressure as 51.93 W at 453 rpm engine speed. The maximum torque was obtained as 1.17 Nm at 2.8 bars Charge Pressure. By comparing experimental work with theoretical work calculated by nodal analysis, the convective heat transfer coefficient at working fluid side of the displacer cylinder was predicted as 447 W/m2 K for air. At maximum shaft power, the internal thermal efficiency of the engine was predicted as 15%.
Haisheng Chen - One of the best experts on this subject based on the ideXlab platform.
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thermodynamic analysis of the cascaded packed bed cryogenic storage based supercritical air energy storage system
Energy Procedia, 2019Co-Authors: Liang Wang, Guoyue Li, Haisheng ChenAbstract:Abstract This paper presents a thermodynamic analysis of a novel stand-alone supercritical air energy storage (SAES) system, based on cascaded packed bed cryogenic storage. This system has the advantages of low cost, high efficiency and safety thanks to the different grade cryogenic energy be transferred and stored in two cascaded packed beds. Thermodynamic analysis results show that the disCharge Pressure and roundtrip efficiency are influenced by component efficiencies, Charge Pressure and middle temperature, and the optimized Charge Pressure and middle temperature are 120.0 bar and -70°C, respectively, no matter how component efficiencies changes. The increasing liquid air storage Pressure reduces the exergy loss in evaporator and condenser and improves the round trip efficiency. Results show that a high round trip efficiency, which is up to 65% could be obtained in this novel supercritical air energy storage system.
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compression performance optimization considering variable Charge Pressure in an adiabatic compressed air energy storage system
Energy, 2018Co-Authors: Yang He, Yujie Xu, Haisheng Chen, Jianqiang DengAbstract:Abstract In an adiabatic compressed air energy storage system (A-CAES), the storage Pressure persistently increases during the energy storage process causing deteriorate of the Charge performance under off-design operating conditions. The compression performance with variable backPressure is essential for the energy storage efficiency and density of A-CAES. A thermodynamic model with energy loss analysis is built up to investigate the performance of a multi-stage centrifugal compressor used in an A-CAES (about 6.0 MW). By energy loss analysis, the blade inlet angle is first focused on to improve the disadvantages of narrow operating conditions and low efficiency at large mass flow rate of the original compressor. Then, the variable rotating speed study is applied on to increase the energy Charge efficiency with a wide storage Pressure range. Using the thermodynamic model, the available rotating speed is determined to be 0.85–1.05 of design value. Furthermore, the rotating speed is optimized to achieve the best efficiency under variable storage Pressures and the corresponding correlation is fitted. Using the optimal rotating speed, the compression efficiency can be kept above 80% while the exergy efficiency is above 82% during the whole energy storage process with a wider storage Pressure.
Hali Karabulu - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamic approach to compare the performance of rhombic drive and crank drive mechanisms for a beta type stirling engine
Applied Thermal Engineering, 2016Co-Authors: Fatih Aksoy, Ca Cina, Hali Karabulu, Hami Solmaz, Yasar Onde Ozgore, Seyfi PolaAbstract:Abstract In this study, the effect of rhombic drive and crank drive mechanisms on the performance of a beta-type Stirling engine was investigated by nodal analysis. Kinematic and thermodynamic relations for both drive mechanisms were introduced and a Fortran code was written for the solution. Piston strokes, cylinder and displacer diameters, hot and cold end temperatures, regenerator volumes and heat transfer surface areas were taken equal for both engines with two different drive mechanisms. In the analysis, air was used as the working gas. Engine power and efficiency were compared for different Charge Pressure values, working gas mass values, heat transfer coefficients and hot end temperatures. Maximum specific engine power was 1410 W/L for the engine with rhombic drive mechanism and 1200 W/L for the engine with crank drive mechanism at 4 bars of Charge Pressure and 500 W/m2K heat transfer coefficient. Rhombic drive mechanism was relatively advantageous at low working gas mass values and high hot end temperatures. In comparison with the engine having rhombic drive mechanism, the relatively poor kinematic behaviour of the engine having crank drive mechanism caused lower engine efficiency and performance. Heat transfer coefficient was also predicted by using an experimental Pressure trace.
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dynamic analysis of a free piston stirling engine working with closed and open thermodynamic cycles
Renewable Energy, 2011Co-Authors: Hali KarabuluAbstract:In free piston Stirling engines the power generated by the engine is related to the length of the piston and displacer strokes. Length of strokes vary with respect to the hot end temperature, external load, Charge Pressure, rod diameter, stiffness of springs, masses of piston and displacer and static positions of the piston and displacer. When the length of displacer and piston strokes exceeds the estimated limits, some mechanical collisions occur between piston and displacer or displacer and cylinder. In this work, the dynamic model of a free piston Stirling engine working with closed and open thermodynamic cycles was derived and numerically solved for an optional pair of the piston and displacer masses. Safe ranges were investigated for the hot end temperature, Charge Pressure, damping coefficient of the piston motion, stiffness of the piston spring and area of the displacer rod. The stiffness of the displacer spring and static positions of the piston and displacer were optimized. Analysis indicated that, a free piston Stirling engine working with a closed thermodynamic cycle performs a stable operation within a small range of the hot end temperature and damping coefficient of the piston motion. By means of inverting the engine into an open-cycle engine, the limited range of the hot end temperature and the damping coefficient of the piston motion were partially enlarged.
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manufacturing and testing of a gamma type stirling engine
Renewable Energy, 2005Co-Authors: Ca Cina, Hali KarabuluAbstract:In this study, a gamma type Stirling engine with 276 cc swept volume was designed and manufactured. The engine was tested with air and helium by using an electrical furnace as heat source. Working characteristics of the engine were obtained within the range of heat source temperature 700–1000 °C and range of Charge Pressure 1–4.5 bar. Maximum power output was obtained with helium at 1000 °C heat source temperature and 4 bar Charge Pressure as 128.3 W. The maximum torque was obtained as 2 N m at 1000 °C heat source temperature and 4 bar helium Charge Pressure. Results were found to be encouraging to initiate a Stirling engine project for 1 kW power output.
Fatih Aksoy - One of the best experts on this subject based on the ideXlab platform.
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a thermodynamic approach to compare the performance of rhombic drive and crank drive mechanisms for a beta type stirling engine
Applied Thermal Engineering, 2016Co-Authors: Fatih Aksoy, Ca Cina, Hali Karabulu, Hami Solmaz, Yasar Onde Ozgore, Seyfi PolaAbstract:Abstract In this study, the effect of rhombic drive and crank drive mechanisms on the performance of a beta-type Stirling engine was investigated by nodal analysis. Kinematic and thermodynamic relations for both drive mechanisms were introduced and a Fortran code was written for the solution. Piston strokes, cylinder and displacer diameters, hot and cold end temperatures, regenerator volumes and heat transfer surface areas were taken equal for both engines with two different drive mechanisms. In the analysis, air was used as the working gas. Engine power and efficiency were compared for different Charge Pressure values, working gas mass values, heat transfer coefficients and hot end temperatures. Maximum specific engine power was 1410 W/L for the engine with rhombic drive mechanism and 1200 W/L for the engine with crank drive mechanism at 4 bars of Charge Pressure and 500 W/m2K heat transfer coefficient. Rhombic drive mechanism was relatively advantageous at low working gas mass values and high hot end temperatures. In comparison with the engine having rhombic drive mechanism, the relatively poor kinematic behaviour of the engine having crank drive mechanism caused lower engine efficiency and performance. Heat transfer coefficient was also predicted by using an experimental Pressure trace.
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thermal performance of a stirling engine powered by a solar simulator
Applied Thermal Engineering, 2015Co-Authors: Fatih Aksoy, Can Cinar, Hamit Solmaz, Yasar Onder Ozgoren, Halit Karabulut, Ahmet UyumazAbstract:Abstract In this study, the performance of a beta type Stirling engine which works at relatively lower temperatures was investigated using 400 W and 1000 W halogen lamps as a heat source and helium as the working fluid. The working fluid was Charged into the engine block and the Pressure of the working fluid was ranged from 1 to 5 bars with 1 bar increments. The halogen lamps were placed into a cavity adjacent to the hot end of the displacer cylinder, which is made of aluminum alloy. In the experiments conducted with 400 W halogen lamp, the temperature of the cavity was 623 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 37.08 W, 1.68 Nm and 9.27%, at 5 bar Charge Pressure. For the 1000 W halogen lamp, the temperature of the cavity was determined to be 873 ± 10 K. The power, torque and thermal efficiency of the engine were determined to be 127.17 W, 3.4 Nm and 12.85%, at the same Charge Pressure. The experimental thermal efficiencies of the engine were also compared with thermodynamic nodal analysis.
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an experimental study on the development of a β type stirling engine for low and moderate temperature heat sources
Applied Energy, 2009Co-Authors: Halit Karabulut, Can Cinar, Huseyin Serdar Yucesu, Fatih AksoyAbstract:In this study, a [beta]-type Stirling engine was designed and manufactured which works at relatively lower temperatures. To increase the heat transfer area, the inner surface of the displacer cylinder was augmented by means of growing spanwise slots. To perform a better approach to the theoretical Stirling cycle, the motion of displacer was governed by a lever. The engine block was used as pressurized working fluid reservoir. The escape of working fluid, through the end-pin bearing of crankshaft, was prevented by means of adapting an oil pool around the end-pin. Experimental results presented in this paper were obtained by testing the engine with air as working fluid. The hot end of the displacer cylinder was heated with a LPG flame and kept about 200 °C constant temperature throughout the testing period. The other end of the displacer cylinder was cooled with a water circulation having 27 °C temperature. Starting from ambient Pressure, the engine was tested at several Charge Pressures up to 4.6 bars. Maximum power output was obtained at 2.8 bars Charge Pressure as 51.93 W at 453 rpm engine speed. The maximum torque was obtained as 1.17 Nm at 2.8 bars Charge Pressure. By comparing experimental work with theoretical work calculated by nodal analysis, the convective heat transfer coefficient at working fluid side of the displacer cylinder was predicted as 447 W/m2 K for air. At maximum shaft power, the internal thermal efficiency of the engine was predicted as 15%.
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an experimental study on the development of a β type stirling engine for low and moderate temperature heat sources
Applied Energy, 2009Co-Authors: Halit Karabulut, Can Cinar, Huseyin Serdar Yucesu, Fatih AksoyAbstract:Abstract In this study, a β-type Stirling engine was designed and manufactured which works at relatively lower temperatures. To increase the heat transfer area, the inner surface of the displacer cylinder was augmented by means of growing spanwise slots. To perform a better approach to the theoretical Stirling cycle, the motion of displacer was governed by a lever. The engine block was used as pressurized working fluid reservoir. The escape of working fluid, through the end-pin bearing of crankshaft, was prevented by means of adapting an oil pool around the end-pin. Experimental results presented in this paper were obtained by testing the engine with air as working fluid. The hot end of the displacer cylinder was heated with a LPG flame and kept about 200 °C constant temperature throughout the testing period. The other end of the displacer cylinder was cooled with a water circulation having 27 °C temperature. Starting from ambient Pressure, the engine was tested at several Charge Pressures up to 4.6 bars. Maximum power output was obtained at 2.8 bars Charge Pressure as 51.93 W at 453 rpm engine speed. The maximum torque was obtained as 1.17 Nm at 2.8 bars Charge Pressure. By comparing experimental work with theoretical work calculated by nodal analysis, the convective heat transfer coefficient at working fluid side of the displacer cylinder was predicted as 447 W/m 2 K for air. At maximum shaft power, the internal thermal efficiency of the engine was predicted as 15%.
Arash Nemati - One of the best experts on this subject based on the ideXlab platform.
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a numerical investigation on the influence of egr in a superCharged si engine fueled with gasoline and alternative fuels
Energy Conversion and Management, 2014Co-Authors: Mohsen Mardi K, Shahram Khalilarya, Arash NematiAbstract:Abstract Alternative fuels are mostly extracted from renewable resources, and their emission levels can be lower than those of traditional fossil-based fuels. A computational fluid dynamics (CFD) method is utilized to investigate the effects of exhaust gas recirculation (EGR) and initial Charge Pressure on the emissions and performance of a SI engine. The engine is fueled separately by gasoline and some of potential alternative fuels including hydrogen, propane, methane, ethanol and methanol. The results of simulation are compared to the experimental data. In all validation cases, experimental and numerical results were observed to have good agreement with each other. The calculations are carried out for EGR ratios between 0% and 20% and four cases of initial Pressure have been mentioned: P in = 1, 1.2, 1.4, 1.6 bar. The effect of EGR on NO x emission of methane is more than other fuels and its effect on IMEP of hydrogen is less than other fuels. From the viewpoints of emission and power, 10% of EGR seems to be the most desirable amount. The most noticeable effect of supercharging is on gasoline unlike hydrogen, which seems to be affected the least. The comparison of results shows that hydrogen due to its high heating value and burning without producing any carbon-based compounds such as HC, CO and CO 2 is an ideal alternative fuel compared to the other fuels.