Browsing by Author "Rajendran, R."

Now showing 1 - 9 of 9

Analyzing design patterns for extensibility
(2011) Annappa, B.; Rajendran, R.; Chandrasekaran, K.; Shet, K.C.
A system is said to be extensible, if any changes can be made to any of the existing system functionalities and/or addition of new functionalities with minimum impact. To achieve extensibility, it has to be planned properly starting from the initial stage of the application development. Keeping in mind all the possible future changes to be made, the designer should select the proper design patterns and finish the design for the application. Once the application design is finished, it should be analyzed to make sure that the application is extensible. � Springer-Verlag Berlin Heidelberg 2011.
Analyzing design patterns for extensibility
(2011) Annappa, B.; Rajendran, R.; Chandrasekaran, K.; Shet, K.C.
A system is said to be extensible, if any changes can be made to any of the existing system functionalities and/or addition of new functionalities with minimum impact. To achieve extensibility, it has to be planned properly starting from the initial stage of the application development. Keeping in mind all the possible future changes to be made, the designer should select the proper design patterns and finish the design for the application. Once the application design is finished, it should be analyzed to make sure that the application is extensible. Â© Springer-Verlag Berlin Heidelberg 2011.
Design and implementation of an automatic traffic sign recognition system on TI OMAP-L138
(2013) Phalguni; Ganapathi, K.; Madumbu, V.; Rajendran, R.; Sumam, David S.
This paper discusses the design and processor implementation of a system that detects and recognizes traffic signs present in an image. Morphological operators, segmentation and contour detection are used for isolating the Regions of Interest (ROIs) from the input image, while five methods - Hu moment matching, histogram based matching, Histogram of Gradients based matching, Euclidean distance based matching and template matching are used for recognizing the traffic sign in the ROI. A classification system based on the shape of the sign is adopted. The performance of the various recognition methods is evaluated by comparing the number of clock cycles used to run the algorithm on the Texas Instruments TMS320C6748 processor. The use of multiple methods for recognizing the traffic signs allows for customization based on the performance of the methods for different datasets. The experiments show that the developed system is robust and well-suited for real-time applications and achieved recognition and classification accuracies of upto 90%. � 2013 IEEE.
Design and implementation of an automatic traffic sign recognition system on TI OMAP-L138
(2013) Phalgun; I Ganapathi, K.; Madumbu, V.; Rajendran, R.; Sumam David, S.
This paper discusses the design and processor implementation of a system that detects and recognizes traffic signs present in an image. Morphological operators, segmentation and contour detection are used for isolating the Regions of Interest (ROIs) from the input image, while five methods - Hu moment matching, histogram based matching, Histogram of Gradients based matching, Euclidean distance based matching and template matching are used for recognizing the traffic sign in the ROI. A classification system based on the shape of the sign is adopted. The performance of the various recognition methods is evaluated by comparing the number of clock cycles used to run the algorithm on the Texas Instruments TMS320C6748 processor. The use of multiple methods for recognizing the traffic signs allows for customization based on the performance of the methods for different datasets. The experiments show that the developed system is robust and well-suited for real-time applications and achieved recognition and classification accuracies of upto 90%. Â© 2013 IEEE.
Experimental and Numerical Investigation of Effusion Cooling Performance Over Combustor Liner Flat Plate Model
(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2019) Jesuraj, J.; Rajendran, R.; Kumar, G.N.; Yepuri, Y.G.; Karthik, M.K.; Ramesha, D.K.
This article presents a study of cooling performance of combustor liner of a gas turbine, using a flat plate model. The combustion process in gas turbine engines liberates very high temperature gases, which impacts the properties of the combustor liner. Hence, cooling of liner is important and is carried out by effusion cooling method. Experiments are carried out over a flat plate with staggered effusion holes. The hot mainstream air flows at a Reynolds number of 2.325 × 105, which indicates a turbulent flow. The coolant to mainstream density ratios of 1.3 and 1.5 is maintained by varying the blowing ratios ranging from 0.5 to 2.5. Test plate surface temperature measurements are recorded by an infrared camera and the overall cooling effectiveness in the flow direction is calculated. Numerical validation for conjugate heat transfer analysis is performed using ANSYS workbench and the temperature contours obtained are compared with infrared camera images. MATLAB program is used to obtain the effectiveness contours for experimental and computational fluid dynamics results. The effectiveness contours are found to be similar, showing the increase in effectiveness with the increase in blowing ratios. Density ratios comparison shows that with the increase in density ratio, the overall cooling effectiveness marginally decreases. © 2018, © 2018 Taylor & Francis Group, LLC.
Experimental investigation of overall cooling effectiveness on combustion chamber liner with and without impingement holes
(2015) Jesuraj, F.; Rajendran, R.; Narayanappa, K.G.; Yepuri, G.B.; Sasikumar, V.; Poozhiyil, S.
The gas turbine combustor liner which is subjected to high temperature requires efficient cooling. In earlier days concept of slot film cooling is utilized in the combustion liners and in modern combustors multiple row film cooling (effusion cooling) is mainly used. This study aims at the experimental investigation of overall film cooling effectiveness of an effusion plate with and without impingement holes at the backside. The experiments are done at different blowing ratios and the surface temperature measurements are taken using infrared thermography. The effusion and impingement holes are arranged in staggered manner on two parallel plates and each effusion hole is surrounded by four impingement holes. Effusion holes are drilled at an angle of 27� and the impingement plate is kept at a distance of 6D away from the effusion plate. The experiments are done on the effusion plate with and without impingement plate at the backside. The results show, increase in cooling effectiveness as the blowing ratio increases. The comparative results shows that at a particular blowing ratio the overall cooling effectiveness is higher for effusion plate with impingement holes at the backside due to the higher convective heat transfer coefficients produced by the impinging jets at the cold side of the effusion plate. � Copyright 2015 by ASME.
Experimental investigation of overall cooling effectiveness on combustion chamber liner with and without impingement holes
(American Society of Mechanical Engineers, 2015) Jesuraj, F.; Rajendran, R.; Gottekere Narayanappa, K.G.; Yepuri, G.B.; Sasikumar, V.; Poozhiyil, S.
The gas turbine combustor liner which is subjected to high temperature requires efficient cooling. In earlier days concept of slot film cooling is utilized in the combustion liners and in modern combustors multiple row film cooling (effusion cooling) is mainly used. This study aims at the experimental investigation of overall film cooling effectiveness of an effusion plate with and without impingement holes at the backside. The experiments are done at different blowing ratios and the surface temperature measurements are taken using infrared thermography. The effusion and impingement holes are arranged in staggered manner on two parallel plates and each effusion hole is surrounded by four impingement holes. Effusion holes are drilled at an angle of 27Â° and the impingement plate is kept at a distance of 6D away from the effusion plate. The experiments are done on the effusion plate with and without impingement plate at the backside. The results show, increase in cooling effectiveness as the blowing ratio increases. The comparative results shows that at a particular blowing ratio the overall cooling effectiveness is higher for effusion plate with impingement holes at the backside due to the higher convective heat transfer coefficients produced by the impinging jets at the cold side of the effusion plate. Â© Copyright 2015 by ASME.
Experimental study of adiabatic cooling effectiveness on an effusion cooled test plate with machined ring geometries
(Begell House Inc. orders@begellhouse.com, 2018) Jesuraj, J.; Rajendran, R.; Kumar, G.N.; Yepuri, Y.G.
The present study deals with experimental investigation of adiabatic cooling effectiveness on an effusion cooled test plate with machined ring geometries. Initial tests were performed on an effusion cooling holes. The cooling effectiveness at the beginning of effusion holes is lower, and it increases in the flow direction mainly due to the additive effect of film cooling effectiveness of the effusion cooling geometry. Subsequent tests were done with machined ring geometries fixed ahead of effusion cooling hole geometry to improve the cooling effectiveness before the beginning of effusion cooling holes. These machined ring geometries act as a wall jet and reduce the hot side heat load by film cooling performance. Tests were performed at a coolant to mainstream density ratio of 1.3 and at blowing ratios ranging from 0.5 to 2.5. Increase in the blowing ratio shows an increase in the cooling effectiveness. Comparison results show that the adiabatic cooling effectiveness increases significantly before the effusion cooling holes in the presence of machined ring geometries at all blowing ratios. © 2018 by Begell House, Inc.
Heat Transfer Studies on Gas Turbine Combustor Liner Cooling
(National Institute of Technology Karnataka, Surathkal, 2019) Felix, J.; Kumar, G. N.; Rajendran, R.
This study deals with the combination of film cooling techniques in an effusion cooled test plate. Geometrical parameters of the effusion cooling test plate have holes of diameter 1 mm, hole angle of 27° and 7.2 mm pitch in both streamwise and spanwise directions. Effusion holes are placed in a staggered manner with 9 holes per row, and there are 13 rows in total. Experimental and numerical investigation of adiabatic cooling effectiveness and convective heat transfer coefficient on an effusion cooled test plate is carried out with and without machined ring geometries upstream. For these tests, the effusion cooling geometrical parameters are scaled up by 3 times. Tests are carried out at blowing ratio ranging from 0.5 to 2.5, coolant to mainstream density ratio of 1.3 and at a mainstream velocity of 20 m/s. The convective heat transfer coefficient investigations are carried out using a constant heat flux surface with coolant and mainstream at the same temperature. Test plate surface temperature measurements are recorded by an infrared camera. Effusion cooling along with machined ring geometries upstream shows higher adiabatic film cooling effectiveness and higher film heat transfer coefficients than effusion cooling alone at all the blowing ratios. Measurements of overall film cooling effectiveness are also carried out in stainless steel effusion cooling test plate of 2 mm thickness with and without machined ring geometries. This comparison result also shows that the overall cooling effectiveness increases significantly before the effusion cooling holes with the presence of machined ring geometries. Another combination of impingement with effusion cooling is studied for an effusion test plate having a 5.4 mm pitch in both the spanwise and streamwise directions. An impingement plate is kept backside of the effusion plate at a distance of 6 mm. The holes in the impingement plate are arranged in a staggered manner such that each effusion hole is surrounded by four impingement holes. The result shows that the effusion cooling with impingement gives higher overall cooling effectiveness than effusion cooling alone. The comparison is made between effusion cooling with impingement and effusion with machined ring geometries. The result shows that the effusion with machined ring geometries has higher overall cooling effectiveness than effusion cooling with impingement. Numerical analysis is performed using ANSYS workbench, and the methodology is validated against the experimental results. The numerical results are matching with the experimental results and the temperature contours obtained are compared with infrared camera images. A MATLAB program isiii used to obtain the effectiveness contours for both the experimental and numerical results.