Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.153.160
G. Adeyemi, O. Odetayo
{"title":"Effects of coolants on the welding zone of mild steel rods in corrosive media","authors":"G. Adeyemi, O. Odetayo","doi":"10.5251/AJSIR.2013.4.1.153.160","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.153.160","url":null,"abstract":"","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"102 1","pages":"153-160"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76897709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.31.35
A. A., E. P. A., Akure Nigeria
The study attempts to enhance the characterization of subsurface reservoirs by improving the spatial prediction of petrophysical properties through integration of petrophysical measurements and 3D seismic observations in a field in the Southern part of Nigeria. This goal is fulfilled by the use of a-priori multi-regression analysis on seismic simultaneous inversion properties, a functional relationship between measured porosity log and seismic inversion properties derived at the well location. Once derived, the relationship is applied to the inversion properties and a porosity cube is generated. Being constrained by physical properties and observations at the well, the resulting porosity estimates from inversion properties are appropriate for making reservoir management decisions. In addition, the result provides a geologically realistic spatial porosity distribution which helps to understand the subsurface reservoirs heterogeneities in the study area.
{"title":"Porosity prediction from seismic inversion properties over ‘XLD’ field, Niger Delta","authors":"A. A., E. P. A., Akure Nigeria","doi":"10.5251/AJSIR.2013.4.1.31.35","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.31.35","url":null,"abstract":"The study attempts to enhance the characterization of subsurface reservoirs by improving the spatial prediction of petrophysical properties through integration of petrophysical measurements and 3D seismic observations in a field in the Southern part of Nigeria. This goal is fulfilled by the use of a-priori multi-regression analysis on seismic simultaneous inversion properties, a functional relationship between measured porosity log and seismic inversion properties derived at the well location. Once derived, the relationship is applied to the inversion properties and a porosity cube is generated. Being constrained by physical properties and observations at the well, the resulting porosity estimates from inversion properties are appropriate for making reservoir management decisions. In addition, the result provides a geologically realistic spatial porosity distribution which helps to understand the subsurface reservoirs heterogeneities in the study area.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"27 1","pages":"31-35"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84531463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.137.152
I. Obi, A. W. Mode
{"title":"Paleocurrent analysis as tool for reservoir property estimation: a case study of Eocene outcrops in Southeastern Nigeria","authors":"I. Obi, A. W. Mode","doi":"10.5251/AJSIR.2013.4.1.137.152","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.137.152","url":null,"abstract":"","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"91 1","pages":"137-152"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78434412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.89.94
B. Shakhreet, S. Bauk, A. Shukri
The Rhizophora spp. wood what is hard and heavy is considered strong in strength and is suitable for structural purposes. Generally, Rhizophora spp. was used in radiation dosimetry research and it is being used in this project too. There are some disadvantages in using the raw (natural) material of Rhizophora spp. in radiation dosimetry research and there is a need to modify this natural wood to be easily used as a phantom in radiation dosimetry. The mass attenuation coefficients (/) of fabricated Rhizophora spp. particleboard were determined for photons in the energy range of 15.77–25.27 keV. This was carried out by studying the attenuation of X-ray fluorescent photons from zirconium, molybdenum, palladium, silver, indium and tin targets. The results were compared with theoretical values for average breast tissues in youngage, middle-age and old-age groups calculated using photon cross section database (XCOM), the well-known code for calculating attenuation coefficients and interaction cross-sections. The measured mass attenuation coefficients were found to be very close to the calculated XCOM values in breasts of old-age group.
{"title":"Mass attenuation coefficients of fabricated Rhizophora spp. particleboard for the 15.77 - 25.27 keV range","authors":"B. Shakhreet, S. Bauk, A. Shukri","doi":"10.5251/AJSIR.2013.4.1.89.94","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.89.94","url":null,"abstract":"The Rhizophora spp. wood what is hard and heavy is considered strong in strength and is suitable for structural purposes. Generally, Rhizophora spp. was used in radiation dosimetry research and it is being used in this project too. There are some disadvantages in using the raw (natural) material of Rhizophora spp. in radiation dosimetry research and there is a need to modify this natural wood to be easily used as a phantom in radiation dosimetry. The mass attenuation coefficients (/) of fabricated Rhizophora spp. particleboard were determined for photons in the energy range of 15.77–25.27 keV. This was carried out by studying the attenuation of X-ray fluorescent photons from zirconium, molybdenum, palladium, silver, indium and tin targets. The results were compared with theoretical values for average breast tissues in youngage, middle-age and old-age groups calculated using photon cross section database (XCOM), the well-known code for calculating attenuation coefficients and interaction cross-sections. The measured mass attenuation coefficients were found to be very close to the calculated XCOM values in breasts of old-age group.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"24 1","pages":"89-94"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88452442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.1.10
K. Kovendan, S. Vincent
In the present study, the toxic effects of arsenic trioxide (Ar2O3) to freshwater fish C. carpio were estimated at different median lethal concentration levels and its influences on the expression of metallothionein (MT) activity in liver and kidney were also observed. During this study, LC50 values were found to be 25.7, 27.4, 29.5, and 32 ppm for the period of 24, 48, 72, and 96 hrs respectively and LC16 and LC84 values of ArO3 also measured. The MT activity was estimated in liver and kidney of fish treated with different concentrations of ArO3 (5, 15, and 20 ppm) at different time intervals (48, 96, and 144 hrs) by using SDS-PAGE technique. From the results, 5 KD and 6 KD polypeptides were known to be metallothionein in liver and kidney respectively when the fishes were treated with different concentrations of arsenic arsenic trioxide. In the present investigation, ArO3 induced significant expression on metallothionein activity and it can be useful biomarker in environmental biomonitoring of arsenic contamination
{"title":"Expression of metallothionein in liver and kidney of freshwater fish Cyprinus carpio var. communis (Linn) exposed to arsenic trioxide","authors":"K. Kovendan, S. Vincent","doi":"10.5251/AJSIR.2013.4.1.1.10","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.1.10","url":null,"abstract":"In the present study, the toxic effects of arsenic trioxide (Ar2O3) to freshwater fish C. carpio were estimated at different median lethal concentration levels and its influences on the expression of metallothionein (MT) activity in liver and kidney were also observed. During this study, LC50 values were found to be 25.7, 27.4, 29.5, and 32 ppm for the period of 24, 48, 72, and 96 hrs respectively and LC16 and LC84 values of ArO3 also measured. The MT activity was estimated in liver and kidney of fish treated with different concentrations of ArO3 (5, 15, and 20 ppm) at different time intervals (48, 96, and 144 hrs) by using SDS-PAGE technique. From the results, 5 KD and 6 KD polypeptides were known to be metallothionein in liver and kidney respectively when the fishes were treated with different concentrations of arsenic arsenic trioxide. In the present investigation, ArO3 induced significant expression on metallothionein activity and it can be useful biomarker in environmental biomonitoring of arsenic contamination","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"11 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89286432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.11.21
K. Oyedele, D. Ogagarue
Seismic and Petro-physical evaluation of EMI field revealed typical structural features of the Niger Delta, namely the roll over anticlines and growth faults with a promising good hydrocarbon accumulation. The extensive faults F2, F3 and F4, which were structure building faults, support suspected hydrocarbon prospects (P2 and P3) which could be explored in the future. The deeper of the two horizons mapped in this study, have better structures for hydrocarbon accumulation with supporting growth faults. The shallower horizon, H1 does not have any faults intersecting it. The two horizons marked the tops of reservoir sands in the field and they both correspond to sequence boundaries as observed on the seismic sections. The Petro-physical values – the Porosity, Net to Gross, Water saturation, Hydrocarbon saturation that were calculated from the POWERLOG software, were almost ideal for the Niger Delta reservoir sands with average porosity values of 0.25, water saturation of 0.42 and average Net to Gross value of 0.85. The lower the water saturation, the higher the hydrocarbon saturation in the reservoir sand, and also the higher the net to gross value, the higher the hydrocarbon saturation.
{"title":"Integration of 3D Seismic and Well log Data In the Optimal Reservoir Characterisation of EMI Field, Offshore Niger Delta Oil Province, Nigeria","authors":"K. Oyedele, D. Ogagarue","doi":"10.5251/AJSIR.2013.4.1.11.21","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.11.21","url":null,"abstract":"Seismic and Petro-physical evaluation of EMI field revealed typical structural features of the Niger Delta, namely the roll over anticlines and growth faults with a promising good hydrocarbon accumulation. The extensive faults F2, F3 and F4, which were structure building faults, support suspected hydrocarbon prospects (P2 and P3) which could be explored in the future. The deeper of the two horizons mapped in this study, have better structures for hydrocarbon accumulation with supporting growth faults. The shallower horizon, H1 does not have any faults intersecting it. The two horizons marked the tops of reservoir sands in the field and they both correspond to sequence boundaries as observed on the seismic sections. The Petro-physical values – the Porosity, Net to Gross, Water saturation, Hydrocarbon saturation that were calculated from the POWERLOG software, were almost ideal for the Niger Delta reservoir sands with average porosity values of 0.25, water saturation of 0.42 and average Net to Gross value of 0.85. The lower the water saturation, the higher the hydrocarbon saturation in the reservoir sand, and also the higher the net to gross value, the higher the hydrocarbon saturation.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"24 1","pages":"11-21"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83310766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.49.58
A. Taiwo, T. Olatayo
Correlation and Regression are the traditional approach of determining relationship between two or more variables. When the variables are multiple and the dependent variable is considered having an explanatory variable, then a Vector Autoregressive model is used to determine the structural relationship between the variables. If these variables are co-integrated, VAR model is not appropriate, but our focus is on the structural relationship and measuring forecast performance of a VAR and Time series regression with Lagged Explanatory Variables. Some Nigerian economic series (Government Revenue and Expenditure, Inflation Rates and Investment) data were analysed and the Root mean Square forecast Error (RMSFE) and Mean Absolute Percentage Forecast Error (MAPFE) are used as measurement criteria. The VAR model was found to be better than Time series regression with Lagged Explanatory Variables model as indicated by Meta diagnostic tools. The forecast values from the VAR model is more realistic and closely reflect the current economic reality in Nigeria indicated by the forecast evaluation tools.
{"title":"Measuring forecasting performance of vector autoregressive and time series regression models","authors":"A. Taiwo, T. Olatayo","doi":"10.5251/AJSIR.2013.4.1.49.58","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.49.58","url":null,"abstract":"Correlation and Regression are the traditional approach of determining relationship between two or more variables. When the variables are multiple and the dependent variable is considered having an explanatory variable, then a Vector Autoregressive model is used to determine the structural relationship between the variables. If these variables are co-integrated, VAR model is not appropriate, but our focus is on the structural relationship and measuring forecast performance of a VAR and Time series regression with Lagged Explanatory Variables. Some Nigerian economic series (Government Revenue and Expenditure, Inflation Rates and Investment) data were analysed and the Root mean Square forecast Error (RMSFE) and Mean Absolute Percentage Forecast Error (MAPFE) are used as measurement criteria. The VAR model was found to be better than Time series regression with Lagged Explanatory Variables model as indicated by Meta diagnostic tools. The forecast values from the VAR model is more realistic and closely reflect the current economic reality in Nigeria indicated by the forecast evaluation tools.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"7 1","pages":"49-58"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87798837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.44.48
M. Akintunde
Drying is purposely meant for preservation at lowest possible cost. The methods of drying can be categorized into two broad headings - Natural and Artificial. In the natural drying method, solar radiation is the major factor required. It has been observed that less than 30% of the radiation from the sun actually reaches the earth surface, the rest are reflected or scattered by the particles of the media through which it passes. As human activities on the earth surface increase, more panicles are released into the atmosphere and hence the rate at which the solar radiation is scattered (or extinct) is at increase. The rate at which the solar radiation reaching the earth surface is scattered was hypothetically measured by drying moist produce in a semi-closed solar drier. The evaporated moisture (forming smog) from the produce was used as the hypothetical atmospheric particles. The effect of this radiation scattering (scattering extinction coefficient, or kvalue) on the drying rate was observed. It was noted that the k-value increases as the amount of particles are increased, and this led to a decrease in drying rate. It was adjudged that, has more particles are released into the atmosphere more radiation will be scattered and drying rate of produce will be reduced. This effect is not known at present due to the general global warming resulting from ozone depletion.
{"title":"Effect of scattering extinction coefficient on drying rate","authors":"M. Akintunde","doi":"10.5251/AJSIR.2013.4.1.44.48","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.44.48","url":null,"abstract":"Drying is purposely meant for preservation at lowest possible cost. The methods of drying can be categorized into two broad headings - Natural and Artificial. In the natural drying method, solar radiation is the major factor required. It has been observed that less than 30% of the radiation from the sun actually reaches the earth surface, the rest are reflected or scattered by the particles of the media through which it passes. As human activities on the earth surface increase, more panicles are released into the atmosphere and hence the rate at which the solar radiation is scattered (or extinct) is at increase. The rate at which the solar radiation reaching the earth surface is scattered was hypothetically measured by drying moist produce in a semi-closed solar drier. The evaporated moisture (forming smog) from the produce was used as the hypothetical atmospheric particles. The effect of this radiation scattering (scattering extinction coefficient, or kvalue) on the drying rate was observed. It was noted that the k-value increases as the amount of particles are increased, and this led to a decrease in drying rate. It was adjudged that, has more particles are released into the atmosphere more radiation will be scattered and drying rate of produce will be reduced. This effect is not known at present due to the general global warming resulting from ozone depletion.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"47 1","pages":"44-48"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77575028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.75.82
E. Ubani, C. Ononuju
Incessant failure and abandonment of public sector projects are still posing serious concern and challenges to the society and other stakeholders in civil engineering and construction industries. The study identifies and examines the salient factors and the warning signals responsible for failure and abandonment of public sector driven civil engineering projects with a view of directing efforts towards forestalling the problems. Opinion survey was adopted with area and judgmental sampling procedures. Primary data based on the identified factors, was captured with the instrument of questionnaire from professionals in civil engineering projects operating in the South East geopolitical zone of Nigeria. The analytical tools used in the study were severity index, spearman’s rank correlation coefficient, relative agreement factors and Kendall’s coefficient of concordance (W.). The rankings of different professionals were significantly correlated. The result of percentage relative agreement factors indicates that the most salient factors causing failure and abandonment of public sector driven civil engineering projects in order of significance are frequent changes in government and political power, unreliable mode of financing and payment of completed work, and project contract sum indirectly used to compensate political big-wigs etc. Wtest further substantiates the results by indicating significant degree of concordance in opinion of experts. The study therefore concludes that politicallyinduced corruption, undefined and non compliance to the agreed mode of financing and payment of completed work are the bane of project success. It is therefore a matter of legislation and policy formulation which should be instituted to avert failure and abandonment of public sector-driven civil engineering projects.
{"title":"A study of failure and abandonment of public sector-driven civil engineering projects in Nigeria: An empirical review","authors":"E. Ubani, C. Ononuju","doi":"10.5251/AJSIR.2013.4.1.75.82","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.75.82","url":null,"abstract":"Incessant failure and abandonment of public sector projects are still posing serious concern and challenges to the society and other stakeholders in civil engineering and construction industries. The study identifies and examines the salient factors and the warning signals responsible for failure and abandonment of public sector driven civil engineering projects with a view of directing efforts towards forestalling the problems. Opinion survey was adopted with area and judgmental sampling procedures. Primary data based on the identified factors, was captured with the instrument of questionnaire from professionals in civil engineering projects operating in the South East geopolitical zone of Nigeria. The analytical tools used in the study were severity index, spearman’s rank correlation coefficient, relative agreement factors and Kendall’s coefficient of concordance (W.). The rankings of different professionals were significantly correlated. The result of percentage relative agreement factors indicates that the most salient factors causing failure and abandonment of public sector driven civil engineering projects in order of significance are frequent changes in government and political power, unreliable mode of financing and payment of completed work, and project contract sum indirectly used to compensate political big-wigs etc. Wtest further substantiates the results by indicating significant degree of concordance in opinion of experts. The study therefore concludes that politicallyinduced corruption, undefined and non compliance to the agreed mode of financing and payment of completed work are the bane of project success. It is therefore a matter of legislation and policy formulation which should be instituted to avert failure and abandonment of public sector-driven civil engineering projects.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"13 1","pages":"75-82"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88942414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-02-01DOI: 10.5251/AJSIR.2013.4.1.123.136
H. AbdelGayed, W. Abdelghaffar
Main swirling flow characteristics are numerically investigated in a typical lean premixed swirl stabilized combustor. The combustor under investigation has been reported previously in the literature for experimentally determining both the combustion instabilities frequency and amplitude with no reference to the detailed flow dynamics inside. It is described in details in the present work. Both realizable Kepsilon and Detached eddy simulation (DES) turbulence models have been used to investigate the flow characteristics inside the combustor. The resultant governing equations have been solved by means of couple pressure based finite volume methodology. ANSYS-Fluent 12 commercial package has been used in the study. Using realizable K-epsilon, a central recirculation zone which is necessary for flame stabilization and efficient combustion has been shown. Also a corner recirculation zone has been detected due to flow separation near combustor dump plane. Using DES, Worm like small scale coherent turbulent structures have been noticed over the vortex break down region followed by a large scale, full length, columnar precessing vortex core along the pipe center line in consistent to previous findings. Results of the current moderate swirl case (S=0.45) have been qualitatively compared with an experimental high swirl case (S=0.6) to determine the effect of swirl on flow characteristics. The high swirl experimental case of S=0.6 resulted in wider central recirculation zone, shorter corner recirculation zone, faster flow reattachment to the wall and slower decay of tangential velocity in comparison of current moderate swirl case of S=0.45. However, further numerical and experimental investigations need to be done in order to gain more insight of the flow dynamics inside the combustor.
{"title":"Main flow characteristics in a lean premixed swirl stabilized gas turbine combustor – Numerical computations","authors":"H. AbdelGayed, W. Abdelghaffar","doi":"10.5251/AJSIR.2013.4.1.123.136","DOIUrl":"https://doi.org/10.5251/AJSIR.2013.4.1.123.136","url":null,"abstract":"Main swirling flow characteristics are numerically investigated in a typical lean premixed swirl stabilized combustor. The combustor under investigation has been reported previously in the literature for experimentally determining both the combustion instabilities frequency and amplitude with no reference to the detailed flow dynamics inside. It is described in details in the present work. Both realizable Kepsilon and Detached eddy simulation (DES) turbulence models have been used to investigate the flow characteristics inside the combustor. The resultant governing equations have been solved by means of couple pressure based finite volume methodology. ANSYS-Fluent 12 commercial package has been used in the study. Using realizable K-epsilon, a central recirculation zone which is necessary for flame stabilization and efficient combustion has been shown. Also a corner recirculation zone has been detected due to flow separation near combustor dump plane. Using DES, Worm like small scale coherent turbulent structures have been noticed over the vortex break down region followed by a large scale, full length, columnar precessing vortex core along the pipe center line in consistent to previous findings. Results of the current moderate swirl case (S=0.45) have been qualitatively compared with an experimental high swirl case (S=0.6) to determine the effect of swirl on flow characteristics. The high swirl experimental case of S=0.6 resulted in wider central recirculation zone, shorter corner recirculation zone, faster flow reattachment to the wall and slower decay of tangential velocity in comparison of current moderate swirl case of S=0.45. However, further numerical and experimental investigations need to be done in order to gain more insight of the flow dynamics inside the combustor.","PeriodicalId":7661,"journal":{"name":"American Journal of Scientific and Industrial Research","volume":"41 1","pages":"123-136"},"PeriodicalIF":0.0,"publicationDate":"2013-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86984041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：