Eşref BAYSAL - Academia.edu (original) (raw)

Papers by Eşref BAYSAL

International Journal of Hydrogen Energy, 2015

Hydrogen production from solar energy is one of the most candidates in near future. Concentric tu... more Hydrogen production from solar energy is one of the most candidates in near future. Concentric tube heat exchangers have been used in concentrated solar power (CSP) plants such as parabolic trough system. In order to be reduced heat exchanger sizes and heat transfer enhancements, in this study, the heat transfer and friction characteristics of a concentric tube heat exchanger with different pitches of coiled wire turbulators were investigated experimentally and numerically. An experimental system was established in order to obtain experimental data. The numerical simulations were performed by using a three dimensional CFD computer code. The experimental, numerical and empirical correlation results were compared with each others for a Reynolds number range from 3000 to 17 000. The results were correlated in the form of Nusselt number as a function of Reynolds number and Prandtl number. The heat transfer enhancements using turbulators were 2.28, 2.07 and 1.95 times better than the smo...

Bu calismada; CANDU yakit cubuklarindaki sicaklik dagilimlari sonlu farklar metodu kullanilarak i... more Bu calismada; CANDU yakit cubuklarindaki sicaklik dagilimlari sonlu farklar metodu kullanilarak incelenmistir. Temel isi iletim denklemleri, tanimlanan sinir sartlariyla birlikte sayisal olarak cozulmustur. Hesaplamalar sonlu farklar metoduna dayali HEATING 7.2 bilgisayar kod sistemi kullanilarak yapilmistir. Elde edilen simulasyon sonuclarina gore, yakit cubuklarinda % 100 UO 2 kullanilmasi sonucu Model j durumunda yakitin merkezinde eksenel cizgideki maksimum sicaklik 1764 °C olarak elde edilirken, UO 2 -ThO 2 yakit karisiminda Model k, Model l ve Model m icin ThO 2 yakit oraninin artmasiyla yakit cubuklarinin merkezindeki eksenel cizgideki sicaklik degerlerinin azaldigi gorulmus, sirasiyla 1213 °C, 944 °C ve 840 °C olarak elde edilmistir. Ayrica; yakit cubuklarinda olusan sicaklik dagiliminin, yakit ve zarf malzemesinin ergime sicakliklarindan daha dusuk oldugu tespit edilmistir.

Kanada Doteryum Uranyum (CANDU) reaktorleri ve Hafif Su Reaktorleri (LWR) dunya enerji ihtiyacini... more Kanada Doteryum Uranyum (CANDU) reaktorleri ve Hafif Su Reaktorleri (LWR) dunya enerji ihtiyacinin karsilanmasinda onemli bir paya sahip olan fisyon reaktorleridir. LWR’lerde yakit olarak zenginlestirilmis uranyum yakiti (~% 3.5 235 U) kullanirken, CANDU reaktorlerinde dogal uranyum (~% 0.71 235 U) kullanilmaktadir. Bu calismada, farkli uranyum (UO 2 , UC, U 3 Si 2 ) yakitlari kullanilarak CANDU reaktorunun notronik performansi, fisyon olabilen yakit uretimi ve nukleer guc uretiminin degisimleri incelenmistir. Hesaplamalar tek boyutlu SCALE 4.4a bilgisayar sistem kodu yardimiyla yapilmistir. Yapilan hesaplamalar sonucunda, k ¥ = 1.06 sinir degerinde bu yakitlar icin yanma dereceleri sirasiyla 7700, 8900 ve 7400 MW.D/MT elde edilmis ve isletim sureleri 170, 260, 190 gun bulunmustur. Burada UC yakitinin, dogal UO 2 ve U 3 Si 2 yakitina oranla kritiklik ve yanma derecesi acisindan cok iyi nukleer performans gosterdigi tespit edilmistir.

Endustriyel proseslerde siklikla kullanilan boru tipi isi degistiricileri, farkli sicakliklardaki... more Endustriyel proseslerde siklikla kullanilan boru tipi isi degistiricileri, farkli sicakliklardaki iki akiskanin birbirine karismadan isinin transfer edilmesine yarayan cihazlardir. Turbulator kullanilmasi ile akisa, akisin sinir tabakasinin butunlugunun bozulup parcalanmasi, akisin oldugu cevreye ek turbulans verilmesi, akisin oldugu cevrede ikincil akislarin meydana gelmesi ve turbulatorlerin hem kanatcik adimlarinin hem de kanatcik acilarinin farklilasmasi sonucunda akiskanin akis mesafesinin uzamasinin saglanmasi gibi etkiler verilmektedir. Bu calismada, turbulatorler zit akisli ic ice borulu isi degistiricide kullanilmistir. Iki boru arasindaki bolgeden 50 l/h sabit hacimsel debide ve 298.14 K sicaklikta su, icteki borudan ise 350 K sicaklikta hava gecmektedir. Icteki boru icine yerlestirilmis halkasal tip turbulatorler farkli adimlarda sayisal olarak incelenmistir. Her bir turbulator icin Reynolds sayisinin 4000 – 26000 araligi icin basinc kayiplari ve surtunme karakteristikler...

Gazi Universitesi Muhendislik Mimarlık Fakultesi Dergisi, 2007

Page 1. Gazi Üniv. Müh. Mim. Fak. Der. J. Fac. Eng. Arch. Gazi Univ. Cilt 22, No 1, 111-119, 2007... more Page 1. Gazi Üniv. Müh. Mim. Fak. Der. J. Fac. Eng. Arch. Gazi Univ. Cilt 22, No 1, 111-119, 2007 Vol 22, No 1, 111-119, 2007 ENERJİ VE EKSERJİ ANALİZ METODUYLA KAYSERİ ŞEKER FABRİKASINDA ENERJİ VERİMLİLİĞİNİN DEĞERLENDİRİLMESİ ...

Plasma Science and Technology

In this paper, neutronic analysis in a laser fusion inertial confinement fusion fission energy (L... more In this paper, neutronic analysis in a laser fusion inertial confinement fusion fission energy (LIFE) engine fuelled plutonium and minor actinides using a MCNP codes was investigated. LIFE engine fuel zone contained 10 vol% TRISO particles and 90 vol% natural lithium coolant mixture. TRISO fuel compositions have Mod①: reactor grade plutonium (RG-Pu), Mod②: weapon grade plutonium (WG-Pu) and Mod③: minor actinides (MAs). Tritium breeding ratios (TBR) were computed as 1.52, 1.62 and 1.46 for Mod①, Mod② and Mod③, respectively. The operation period was computed as ∼21 years when the reference TBR>1.05 for a selfsustained reactor for all investigated cases. Blanket energy multiplication values (M) were calculated as 4.18, 4.95 and 3.75 for Mod①, Mod② and Mod③, respectively. The burnup (BU) values were obtained as ∼1230, ∼1550 and ∼1060 GWd tM-1 , respectively. As a result, the higher BU were provided with using TRISO particles for all cases in LIFE engine.

International Journal of Hydrogen Energy, 2015

International Journal of Hydrogen Energy, 2015

International Journal of Hydrogen Energy, 2015

Hydrogen production from solar energy is one of the most candidates in near future. Concentric tu... more Hydrogen production from solar energy is one of the most candidates in near future. Concentric tube heat exchangers have been used in concentrated solar power (CSP) plants such as parabolic trough system. In order to be reduced heat exchanger sizes and heat transfer enhancements, in this study, the heat transfer and friction characteristics of a concentric tube heat exchanger with different pitches of coiled wire turbulators were investigated experimentally and numerically. An experimental system was established in order to obtain experimental data. The numerical simulations were performed by using a three dimensional CFD computer code. The experimental, numerical and empirical correlation results were compared with each others for a Reynolds number range from 3000 to 17 000. The results were correlated in the form of Nusselt number as a function of Reynolds number and Prandtl number. The heat transfer enhancements using turbulators were 2.28, 2.07 and 1.95 times better than the smo...

Bu calismada; CANDU yakit cubuklarindaki sicaklik dagilimlari sonlu farklar metodu kullanilarak i... more Bu calismada; CANDU yakit cubuklarindaki sicaklik dagilimlari sonlu farklar metodu kullanilarak incelenmistir. Temel isi iletim denklemleri, tanimlanan sinir sartlariyla birlikte sayisal olarak cozulmustur. Hesaplamalar sonlu farklar metoduna dayali HEATING 7.2 bilgisayar kod sistemi kullanilarak yapilmistir. Elde edilen simulasyon sonuclarina gore, yakit cubuklarinda % 100 UO 2 kullanilmasi sonucu Model j durumunda yakitin merkezinde eksenel cizgideki maksimum sicaklik 1764 °C olarak elde edilirken, UO 2 -ThO 2 yakit karisiminda Model k, Model l ve Model m icin ThO 2 yakit oraninin artmasiyla yakit cubuklarinin merkezindeki eksenel cizgideki sicaklik degerlerinin azaldigi gorulmus, sirasiyla 1213 °C, 944 °C ve 840 °C olarak elde edilmistir. Ayrica; yakit cubuklarinda olusan sicaklik dagiliminin, yakit ve zarf malzemesinin ergime sicakliklarindan daha dusuk oldugu tespit edilmistir.

Kanada Doteryum Uranyum (CANDU) reaktorleri ve Hafif Su Reaktorleri (LWR) dunya enerji ihtiyacini... more Kanada Doteryum Uranyum (CANDU) reaktorleri ve Hafif Su Reaktorleri (LWR) dunya enerji ihtiyacinin karsilanmasinda onemli bir paya sahip olan fisyon reaktorleridir. LWR’lerde yakit olarak zenginlestirilmis uranyum yakiti (~% 3.5 235 U) kullanirken, CANDU reaktorlerinde dogal uranyum (~% 0.71 235 U) kullanilmaktadir. Bu calismada, farkli uranyum (UO 2 , UC, U 3 Si 2 ) yakitlari kullanilarak CANDU reaktorunun notronik performansi, fisyon olabilen yakit uretimi ve nukleer guc uretiminin degisimleri incelenmistir. Hesaplamalar tek boyutlu SCALE 4.4a bilgisayar sistem kodu yardimiyla yapilmistir. Yapilan hesaplamalar sonucunda, k ¥ = 1.06 sinir degerinde bu yakitlar icin yanma dereceleri sirasiyla 7700, 8900 ve 7400 MW.D/MT elde edilmis ve isletim sureleri 170, 260, 190 gun bulunmustur. Burada UC yakitinin, dogal UO 2 ve U 3 Si 2 yakitina oranla kritiklik ve yanma derecesi acisindan cok iyi nukleer performans gosterdigi tespit edilmistir.

Endustriyel proseslerde siklikla kullanilan boru tipi isi degistiricileri, farkli sicakliklardaki... more Endustriyel proseslerde siklikla kullanilan boru tipi isi degistiricileri, farkli sicakliklardaki iki akiskanin birbirine karismadan isinin transfer edilmesine yarayan cihazlardir. Turbulator kullanilmasi ile akisa, akisin sinir tabakasinin butunlugunun bozulup parcalanmasi, akisin oldugu cevreye ek turbulans verilmesi, akisin oldugu cevrede ikincil akislarin meydana gelmesi ve turbulatorlerin hem kanatcik adimlarinin hem de kanatcik acilarinin farklilasmasi sonucunda akiskanin akis mesafesinin uzamasinin saglanmasi gibi etkiler verilmektedir. Bu calismada, turbulatorler zit akisli ic ice borulu isi degistiricide kullanilmistir. Iki boru arasindaki bolgeden 50 l/h sabit hacimsel debide ve 298.14 K sicaklikta su, icteki borudan ise 350 K sicaklikta hava gecmektedir. Icteki boru icine yerlestirilmis halkasal tip turbulatorler farkli adimlarda sayisal olarak incelenmistir. Her bir turbulator icin Reynolds sayisinin 4000 – 26000 araligi icin basinc kayiplari ve surtunme karakteristikler...

Gazi Universitesi Muhendislik Mimarlık Fakultesi Dergisi, 2007

Page 1. Gazi Üniv. Müh. Mim. Fak. Der. J. Fac. Eng. Arch. Gazi Univ. Cilt 22, No 1, 111-119, 2007... more Page 1. Gazi Üniv. Müh. Mim. Fak. Der. J. Fac. Eng. Arch. Gazi Univ. Cilt 22, No 1, 111-119, 2007 Vol 22, No 1, 111-119, 2007 ENERJİ VE EKSERJİ ANALİZ METODUYLA KAYSERİ ŞEKER FABRİKASINDA ENERJİ VERİMLİLİĞİNİN DEĞERLENDİRİLMESİ ...

Plasma Science and Technology

In this paper, neutronic analysis in a laser fusion inertial confinement fusion fission energy (L... more In this paper, neutronic analysis in a laser fusion inertial confinement fusion fission energy (LIFE) engine fuelled plutonium and minor actinides using a MCNP codes was investigated. LIFE engine fuel zone contained 10 vol% TRISO particles and 90 vol% natural lithium coolant mixture. TRISO fuel compositions have Mod①: reactor grade plutonium (RG-Pu), Mod②: weapon grade plutonium (WG-Pu) and Mod③: minor actinides (MAs). Tritium breeding ratios (TBR) were computed as 1.52, 1.62 and 1.46 for Mod①, Mod② and Mod③, respectively. The operation period was computed as ∼21 years when the reference TBR>1.05 for a selfsustained reactor for all investigated cases. Blanket energy multiplication values (M) were calculated as 4.18, 4.95 and 3.75 for Mod①, Mod② and Mod③, respectively. The burnup (BU) values were obtained as ∼1230, ∼1550 and ∼1060 GWd tM-1 , respectively. As a result, the higher BU were provided with using TRISO particles for all cases in LIFE engine.

International Journal of Hydrogen Energy, 2015

International Journal of Hydrogen Energy, 2015