YASAR PANCAR | Eskisehir Osmangazi University, Turkey (original) (raw)

Papers by YASAR PANCAR

ESOGÜ, Mühendislik Mimarlık Fakültesi, Makine Mühendisliği Bölümü, 2008

CERN European Organization for Nuclear Research - Zenodo, Jul 18, 2022

The Abrasive Water Jet (AWJ) cutting process uses abrasive particles in a highly pressurized wate... more The Abrasive Water Jet (AWJ) cutting process uses abrasive particles in a highly pressurized water jet for cutting the metallic and non-metallic materials. It has more advantageous features compared to other cutting methods. AWJ can eliminate toxic gases, recast layers, slag, and thermal stresses. In this study, the result of the AWJ cutting experiments will be presented. The experiments were performed on two types of steel materials which are widely used in the aviation and naval industry. These materials are BS 7191 355 EMZ and ASTM A516 Gr.60 plates of steel. In total, 180 cuttings were performed with pre-assigned water jet pressure, speed, and diameter parameters. At the end of the experimental study, it was determined that; between both steels; BS 7191 355 EMZ provides a comparatively higher surface quality than ASTM A516 Gr.60 using a small water jet diameter, low rate speed, and low pressure.

Uludağ University Journal of The Faculty of Engineering, Apr 1, 2008

Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gi... more Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gibi geometrik faktörlere bağlı olarak değişmektedir. Kanat sayısının düşük olmasından dolayı oluşan hidrolik kayıplar, iki ana kanat arasındaki merkez akış hattı üzerine ara kanatçık yerleştirilmesi ile azaltılabilir. Uygulamada kanat sayısı genellikle tecrübe edilmiş değerlere bağlı olarak seçildikten sonra, kanatların çıkış açısının hesabı yapılır. Bu çalışmada; kanat sayısı z = 3 ve z = 4 olan düşük kanat sayılı ve düşük kanat çıkış açısına (β 2K =15 0) sahip dalgıç pompa çarklarına; iki ana kanadın merkez akış hattı üzerine ana kanat boyunun % 25-35-50-60 ve 80 oranlarında ara kanatçıklar yerleştirerek, dalgıç pompa performansı üzerine etkileri deneysel olarak incelenmiş ve H m =f (Q) karakteristiği kararlı hale getirilerek verimde artış sağlanmıştır.

Bu caltsmada, loblu viskoz pompalartn analiz ve optimizasyonuna yonelik yeni bir dizayn gelistiri... more Bu caltsmada, loblu viskoz pompalartn analiz ve optimizasyonuna yonelik yeni bir dizayn gelistirilmistir. Bu yeni dizayn, yaridairesel loblu pompalartn on dizayntnin aksine duz loblartn durumunu ortaya koymaktadir. Duz loblartn geometrisi ise yartdairesel lob geometrisindeki actk cozume aynen uymaktadtr. Bu geometrilere gore yaklasimlar elde edilmis ve yuksek ve dusuk sekil faktor stntrlart kullanilarak yaklastmlartn dogrulugu kanttlanmtsttr. Lob geometrisi, maksimum pompa lama kapasitesini elde etmek iirere optimize edilmistir. Optimizasyon sonuclart duz loblu pompalartn yartdairesel loblu pompalara gore daha ustun oldugunu gostermistir.

Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gi... more Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gibi geometrik faktörlere bağlı olarak değişmektedir. Kanat sayısının düşük olmasından dolayı oluşan hidrolik kayıplar, iki ana kanat arasındaki merkez akış hattı üzerine ara kanatçık yerleştirilmesi ile azaltılabilir. Uygulamada kanat sayısı genellikle tecrübe edilmiş değerlere bağlı olarak seçildikten sonra, kanatların çıkış açısının hesabı yapılır. Bu çalışmada; kanat sayısı z = 3 ve z = 4 olan düşük kanat sayılı ve düşük kanat çıkış açısına (β 2K =15 0) sahip dalgıç pompa çarklarına; iki ana kanadın merkez akış hattı üzerine ana kanat boyunun % 25-35-50-60 ve 80 oranlarında ara kanatçıklar yerleştirerek, dalgıç pompa performansı üzerine etkileri deneysel olarak incelenmiş ve H m =f (Q) karakteristiği kararlı hale getirilerek verimde artış sağlanmıştır.

Mathematical and Computational Applications, 2006

The fuel injection pressure is one of the significant operating parameters affects atomization of... more The fuel injection pressure is one of the significant operating parameters affects atomization of fuel and mixture formation; therefore, it determines the performance and emissions of a diesel engine. Increasing the fuel injection pressure decrease the particle diameter and caused the diesel fuel spray to vaporize quickly. However, with decreasing fuel particles their inertia will also decrease and for this reason fuel can not penetrate deeply into the combustion chamber. In this study, artificial neural-networks (ANNs) are used to determine the effects of injection pressure on smoke emissions and engine performance in a diesel engine. Experimental studies were used to obtain training and test data. Injection pressure was changed from 100bar to 300bar in experiment (standard injection pressure of test engine is 150bar). Injection pressure and engine speed have been used as the input layer; smoke emission, engine torque and specific fuel consumption have been used as the output layer. Two different training algorithms were studied. The best results were obtained from Levenberg-Marquardt (LM) and Scaled Conjugate gradient (SCG) algorithms with 11 neurons. However, The LM algorithm is faster than the SCG algorithm, and its error values are smaller than those of the SCGs. For the torque with LM algorithm, fraction of variance (R 2) and mean absolute percentage error (MAPE) were found to be 0.9927 and 7.2108%, respectively. Similarly, for the specific fuel consumption (SFC), R 2 and MAPE were calculated as 0.9872 and 6.0261%, respectively. For the torque with SCG algorithm, R 2 and MAPE were found to be 0.9879 and 9.0026%, respectively. Similarly, for the specific fuel consumption (SFC), R 2 and MAPE were calculated as 0.9793 and 8.7974%, respectively. So, these ANN predicted results can be considered within acceptable limits and the results show good agreement between predicted and experimental values.

Energy Conversion and Management, 2006

Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pum... more Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pump performance and energy consumption. Deep well pumps with splitter blades (DWPwsb) are manufactured to achieve energy saving and improve efficiency. Splitter blades are generally located at the centerline of the main blades. Blade number and blade discharge angle should be conveniently determined when splitter blades are used on the impellers. In this study, impellers having different numbers of blades (z = 5, 6, 7) with and without splitter blades (35%, 60% and 80% of the main blade length) were tested in a deep well pump. Tests have been conducted on a total of 12 impellers, and the characteristics of deep well pumps without splitter blade (DWPwosb) and DWPwsb were obtained experimentally. These results show that splitter blades cause negative effects on pump performance in impellers with blade numbers of 6 and 7. When the splitter blade is added to the impeller with the blade number of 5, the efficiency increases with flow up to 10 l/s flow rate, after which it decreases as the splitter blade length increases. The highest efficiency and the lowest energy consumption were obtained in DWPwsb with 80% of the main blade length. At the best efficiency point (b.e.p), an energy saving of 6.6% and an improvement of 1.14% in efficiency were achieved. An analysis of the additional cost of the splitter blade and the application in an agricultural area were performed.

The Society for Aerospace System Engineering, Sep 30, 2009

Journal of Energy Resources Technology, 2007

ABSTRACT Impellers with splitter blades have been used in turbomachinery design for both pumps an... more ABSTRACT Impellers with splitter blades have been used in turbomachinery design for both pumps and compressors. Increasing the number of blades increases the head of the pump, however it causes a decrease in efficiency due to the blockage effect of the blade thickness and firiction. The impellers with splitter blades between two long blades can be used to alleviate the serious clogging at the inlet of the impeller caused by more blades. In this study, impellers having a different number of blades (z=3, 4, 5, 6, and 7) with and without splitter blades (25, 35, 50, 60, and 80% of the main blade length) were tested in a deep well pump. The effects of the main blade number and lengths of splitter blades oil the pump performance have been investigated. While the number of main blades and the lengths of the splitter blades of a principal impeller were changed, the other parameters such as pump casing, blade inlet and outlet angles, blade thickness, impeller inlet and outlet diameters, were kept the same.

Energy Conversion and Management, 2006

Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pum... more Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pump performance and energy consumption. Deep well pumps with splitter blades (DWPwsb) are manufactured to achieve energy saving and improve efficiency. Splitter blades are generally located at the centerline of the main blades. Blade number and blade discharge angle should be conveniently determined when splitter blades are used on the impellers.

Applied Energy, 2006

In countries that import most of their energy, like Turkey, energy saving and the effective usage... more In countries that import most of their energy, like Turkey, energy saving and the effective usage of energy become much more important. Energy consumption for heating is too high in Turkey because buildings have almost no insulation. Also the high prices of heating energy in Turkey, emphasize the need for energy saving. Therefore, the optimum insulation-thickness of the external wall for the five different energy-sources (coal, natural gas, LPG, fuel oil and electricity) and two different insulation materials (expanded polystyrene, rock wool) are calculated for Denizli. The optimization is based on a life-cycle cost analysis. According to the results, the optimum has been obtained by using coal as the energy source and expanded polystyrene as the insulating material. When the optimum insulation-thickness is used the life cycle saving and payback period are 14.09 $/m 2 and 1.43 years, respectively. .tr (Ö . Altan Dombaycı). Applied Energy 83 (2006) 921-928 www.elsevier.com/locate/apenergy APPLIED ENERGY

mmo.org.tr

Son 40 yıldır hidrolik sistem kullanımı oldukça gelişmiştir. Daha güçlü, hızlı ve çok yönlü kulla... more Son 40 yıldır hidrolik sistem kullanımı oldukça gelişmiştir. Daha güçlü, hızlı ve çok yönlü kullanım, gelişmiş hidrolik çeviriciler ve sistem kontrolleri sayesinde gerçekleşmektedir. Bilineceği üzere ağır yükler, hızlı çevrimler büyük kapasiteli ve yüksek basınçlara çıkabilen pompalar gerektirirler. Ancak yüksek basınçta çalışan sistem elemanları yüksek gerilmeye maruz kalır. Bundan dolayı arıza sayısını azaltmak ve çalışma ömrünü artırmak için hidrolik sistem dolayısıyla hidrolik pompa bakımı, her geçen gün daha da önem kazanmaktadır. En çok karşılaşılan pompa arızalarının % 80'i hatalı çalıştırma ve bakımdan oluşmaktadır.

Mathematical and …, Jan 1, 2010

Artificial Neural Network (ANN) was used to predict the effects of splitter blades in a semi-open... more Artificial Neural Network (ANN) was used to predict the effects of splitter blades in a semi-open impeller on centrifugal pump performance. The characteristics of this impeller were compared with those of impellers without splitter blades. Experimental results for lengths of splitter blades in ratio of 1/3, 2/3, and 3/3 of the main blade length were evaluated by different ANN training algorithm. Training and test data were obtained from experimental studies. The best training algorithm and number of neurons were determined. The values of head, efficiency, and effective power were estimated in a semi-open impeller with splitter blades in ratio of 3/6 and 5/6 of the main blade length at the best efficiency point (b.e.p.). Here, as the splitter blade length increases; the flow rate and power increases, the efficiency decrease. All of the estimated values of performance in a semi-open impeller with splitter blades indicate the model works in line with expectations. Experimental studies to determine head, efficiency and effective power consumption in different types of pumps are complex, time consuming, and costly. It also requires specific measurement tools to obtain the characteristics values of pump. To overcome these difficulties, an ANN can be used for prediction of pump performance in semi open impeller.

ESOGÜ, Mühendislik Mimarlık Fakültesi, Makine Mühendisliği Bölümü, 2008

CERN European Organization for Nuclear Research - Zenodo, Jul 18, 2022

The Abrasive Water Jet (AWJ) cutting process uses abrasive particles in a highly pressurized wate... more The Abrasive Water Jet (AWJ) cutting process uses abrasive particles in a highly pressurized water jet for cutting the metallic and non-metallic materials. It has more advantageous features compared to other cutting methods. AWJ can eliminate toxic gases, recast layers, slag, and thermal stresses. In this study, the result of the AWJ cutting experiments will be presented. The experiments were performed on two types of steel materials which are widely used in the aviation and naval industry. These materials are BS 7191 355 EMZ and ASTM A516 Gr.60 plates of steel. In total, 180 cuttings were performed with pre-assigned water jet pressure, speed, and diameter parameters. At the end of the experimental study, it was determined that; between both steels; BS 7191 355 EMZ provides a comparatively higher surface quality than ASTM A516 Gr.60 using a small water jet diameter, low rate speed, and low pressure.

Uludağ University Journal of The Faculty of Engineering, Apr 1, 2008

Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gi... more Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gibi geometrik faktörlere bağlı olarak değişmektedir. Kanat sayısının düşük olmasından dolayı oluşan hidrolik kayıplar, iki ana kanat arasındaki merkez akış hattı üzerine ara kanatçık yerleştirilmesi ile azaltılabilir. Uygulamada kanat sayısı genellikle tecrübe edilmiş değerlere bağlı olarak seçildikten sonra, kanatların çıkış açısının hesabı yapılır. Bu çalışmada; kanat sayısı z = 3 ve z = 4 olan düşük kanat sayılı ve düşük kanat çıkış açısına (β 2K =15 0) sahip dalgıç pompa çarklarına; iki ana kanadın merkez akış hattı üzerine ana kanat boyunun % 25-35-50-60 ve 80 oranlarında ara kanatçıklar yerleştirerek, dalgıç pompa performansı üzerine etkileri deneysel olarak incelenmiş ve H m =f (Q) karakteristiği kararlı hale getirilerek verimde artış sağlanmıştır.

Bu caltsmada, loblu viskoz pompalartn analiz ve optimizasyonuna yonelik yeni bir dizayn gelistiri... more Bu caltsmada, loblu viskoz pompalartn analiz ve optimizasyonuna yonelik yeni bir dizayn gelistirilmistir. Bu yeni dizayn, yaridairesel loblu pompalartn on dizayntnin aksine duz loblartn durumunu ortaya koymaktadir. Duz loblartn geometrisi ise yartdairesel lob geometrisindeki actk cozume aynen uymaktadtr. Bu geometrilere gore yaklasimlar elde edilmis ve yuksek ve dusuk sekil faktor stntrlart kullanilarak yaklastmlartn dogrulugu kanttlanmtsttr. Lob geometrisi, maksimum pompa lama kapasitesini elde etmek iirere optimize edilmistir. Optimizasyon sonuclart duz loblu pompalartn yartdairesel loblu pompalara gore daha ustun oldugunu gostermistir.

Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gi... more Debi-yük karakteristiğinin kararlılık durumu; kanat sayısı, kanat çıkış açısı, çark çıkış çapı gibi geometrik faktörlere bağlı olarak değişmektedir. Kanat sayısının düşük olmasından dolayı oluşan hidrolik kayıplar, iki ana kanat arasındaki merkez akış hattı üzerine ara kanatçık yerleştirilmesi ile azaltılabilir. Uygulamada kanat sayısı genellikle tecrübe edilmiş değerlere bağlı olarak seçildikten sonra, kanatların çıkış açısının hesabı yapılır. Bu çalışmada; kanat sayısı z = 3 ve z = 4 olan düşük kanat sayılı ve düşük kanat çıkış açısına (β 2K =15 0) sahip dalgıç pompa çarklarına; iki ana kanadın merkez akış hattı üzerine ana kanat boyunun % 25-35-50-60 ve 80 oranlarında ara kanatçıklar yerleştirerek, dalgıç pompa performansı üzerine etkileri deneysel olarak incelenmiş ve H m =f (Q) karakteristiği kararlı hale getirilerek verimde artış sağlanmıştır.

Mathematical and Computational Applications, 2006

The fuel injection pressure is one of the significant operating parameters affects atomization of... more The fuel injection pressure is one of the significant operating parameters affects atomization of fuel and mixture formation; therefore, it determines the performance and emissions of a diesel engine. Increasing the fuel injection pressure decrease the particle diameter and caused the diesel fuel spray to vaporize quickly. However, with decreasing fuel particles their inertia will also decrease and for this reason fuel can not penetrate deeply into the combustion chamber. In this study, artificial neural-networks (ANNs) are used to determine the effects of injection pressure on smoke emissions and engine performance in a diesel engine. Experimental studies were used to obtain training and test data. Injection pressure was changed from 100bar to 300bar in experiment (standard injection pressure of test engine is 150bar). Injection pressure and engine speed have been used as the input layer; smoke emission, engine torque and specific fuel consumption have been used as the output layer. Two different training algorithms were studied. The best results were obtained from Levenberg-Marquardt (LM) and Scaled Conjugate gradient (SCG) algorithms with 11 neurons. However, The LM algorithm is faster than the SCG algorithm, and its error values are smaller than those of the SCGs. For the torque with LM algorithm, fraction of variance (R 2) and mean absolute percentage error (MAPE) were found to be 0.9927 and 7.2108%, respectively. Similarly, for the specific fuel consumption (SFC), R 2 and MAPE were calculated as 0.9872 and 6.0261%, respectively. For the torque with SCG algorithm, R 2 and MAPE were found to be 0.9879 and 9.0026%, respectively. Similarly, for the specific fuel consumption (SFC), R 2 and MAPE were calculated as 0.9793 and 8.7974%, respectively. So, these ANN predicted results can be considered within acceptable limits and the results show good agreement between predicted and experimental values.

Energy Conversion and Management, 2006

Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pum... more Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pump performance and energy consumption. Deep well pumps with splitter blades (DWPwsb) are manufactured to achieve energy saving and improve efficiency. Splitter blades are generally located at the centerline of the main blades. Blade number and blade discharge angle should be conveniently determined when splitter blades are used on the impellers. In this study, impellers having different numbers of blades (z = 5, 6, 7) with and without splitter blades (35%, 60% and 80% of the main blade length) were tested in a deep well pump. Tests have been conducted on a total of 12 impellers, and the characteristics of deep well pumps without splitter blade (DWPwosb) and DWPwsb were obtained experimentally. These results show that splitter blades cause negative effects on pump performance in impellers with blade numbers of 6 and 7. When the splitter blade is added to the impeller with the blade number of 5, the efficiency increases with flow up to 10 l/s flow rate, after which it decreases as the splitter blade length increases. The highest efficiency and the lowest energy consumption were obtained in DWPwsb with 80% of the main blade length. At the best efficiency point (b.e.p), an energy saving of 6.6% and an improvement of 1.14% in efficiency were achieved. An analysis of the additional cost of the splitter blade and the application in an agricultural area were performed.

The Society for Aerospace System Engineering, Sep 30, 2009

Journal of Energy Resources Technology, 2007

ABSTRACT Impellers with splitter blades have been used in turbomachinery design for both pumps an... more ABSTRACT Impellers with splitter blades have been used in turbomachinery design for both pumps and compressors. Increasing the number of blades increases the head of the pump, however it causes a decrease in efficiency due to the blockage effect of the blade thickness and firiction. The impellers with splitter blades between two long blades can be used to alleviate the serious clogging at the inlet of the impeller caused by more blades. In this study, impellers having a different number of blades (z=3, 4, 5, 6, and 7) with and without splitter blades (25, 35, 50, 60, and 80% of the main blade length) were tested in a deep well pump. The effects of the main blade number and lengths of splitter blades oil the pump performance have been investigated. While the number of main blades and the lengths of the splitter blades of a principal impeller were changed, the other parameters such as pump casing, blade inlet and outlet angles, blade thickness, impeller inlet and outlet diameters, were kept the same.

Energy Conversion and Management, 2006

Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pum... more Design parameters, like blade number, blade outlet angle and impeller outlet diameter, affect pump performance and energy consumption. Deep well pumps with splitter blades (DWPwsb) are manufactured to achieve energy saving and improve efficiency. Splitter blades are generally located at the centerline of the main blades. Blade number and blade discharge angle should be conveniently determined when splitter blades are used on the impellers.

Applied Energy, 2006

In countries that import most of their energy, like Turkey, energy saving and the effective usage... more In countries that import most of their energy, like Turkey, energy saving and the effective usage of energy become much more important. Energy consumption for heating is too high in Turkey because buildings have almost no insulation. Also the high prices of heating energy in Turkey, emphasize the need for energy saving. Therefore, the optimum insulation-thickness of the external wall for the five different energy-sources (coal, natural gas, LPG, fuel oil and electricity) and two different insulation materials (expanded polystyrene, rock wool) are calculated for Denizli. The optimization is based on a life-cycle cost analysis. According to the results, the optimum has been obtained by using coal as the energy source and expanded polystyrene as the insulating material. When the optimum insulation-thickness is used the life cycle saving and payback period are 14.09 $/m 2 and 1.43 years, respectively. .tr (Ö . Altan Dombaycı). Applied Energy 83 (2006) 921-928 www.elsevier.com/locate/apenergy APPLIED ENERGY

mmo.org.tr

Son 40 yıldır hidrolik sistem kullanımı oldukça gelişmiştir. Daha güçlü, hızlı ve çok yönlü kulla... more Son 40 yıldır hidrolik sistem kullanımı oldukça gelişmiştir. Daha güçlü, hızlı ve çok yönlü kullanım, gelişmiş hidrolik çeviriciler ve sistem kontrolleri sayesinde gerçekleşmektedir. Bilineceği üzere ağır yükler, hızlı çevrimler büyük kapasiteli ve yüksek basınçlara çıkabilen pompalar gerektirirler. Ancak yüksek basınçta çalışan sistem elemanları yüksek gerilmeye maruz kalır. Bundan dolayı arıza sayısını azaltmak ve çalışma ömrünü artırmak için hidrolik sistem dolayısıyla hidrolik pompa bakımı, her geçen gün daha da önem kazanmaktadır. En çok karşılaşılan pompa arızalarının % 80'i hatalı çalıştırma ve bakımdan oluşmaktadır.

Mathematical and …, Jan 1, 2010

Artificial Neural Network (ANN) was used to predict the effects of splitter blades in a semi-open... more Artificial Neural Network (ANN) was used to predict the effects of splitter blades in a semi-open impeller on centrifugal pump performance. The characteristics of this impeller were compared with those of impellers without splitter blades. Experimental results for lengths of splitter blades in ratio of 1/3, 2/3, and 3/3 of the main blade length were evaluated by different ANN training algorithm. Training and test data were obtained from experimental studies. The best training algorithm and number of neurons were determined. The values of head, efficiency, and effective power were estimated in a semi-open impeller with splitter blades in ratio of 3/6 and 5/6 of the main blade length at the best efficiency point (b.e.p.). Here, as the splitter blade length increases; the flow rate and power increases, the efficiency decrease. All of the estimated values of performance in a semi-open impeller with splitter blades indicate the model works in line with expectations. Experimental studies to determine head, efficiency and effective power consumption in different types of pumps are complex, time consuming, and costly. It also requires specific measurement tools to obtain the characteristics values of pump. To overcome these difficulties, an ANN can be used for prediction of pump performance in semi open impeller.