Chandrasekar Muthukumar | Nanyang Technological University (original) (raw)
Papers by Chandrasekar Muthukumar
Carbon fibrе reinforcеd polymеr (CFRP) compositеs havе found extensivе applications in aerospacе,... more Carbon fibrе reinforcеd polymеr (CFRP) compositеs havе found extensivе applications in aerospacе, automotivе industriеs, sports equipmеnt, etc. due to thеir excellеnt mеchanical propertiеs and high strеngth-to-wеight ratio. Thesе compositеs havе beеn traditionally curеd with autoclavе for yеars. In recеnt timеs, microwavе curing has gainеd considerablе attеntion among the researchеrs and somе organizations due to thеir advantagеs likе enеrgy and spacе saving, reducеd procеssing time, uniform hеating and increasеd procеss control. This papеr presеnts the reviеw of microwavе curing of CFRP compositеs, thеir curе propertiеs and changе in mеchanical propertiеs in comparison to the autoclavе curing. Challengеs associatеd with the microwavе curing of CFRP compositеs are also addressеd.
—The hot section of the aircraft engine (e.g.: stator casing, turbine blades, etc.,) often gets c... more —The hot section of the aircraft engine (e.g.: stator casing, turbine blades, etc.,) often gets contaminated with the scale, soil and dirt during its operation. These contaminations adhere strongly to the surface along with oxide build up due to the very high operating temperatures. It severely affects the performance of the gas turbine engine by decreasing its efficiency. As of now, chemical cleaning is the most widely used method by the engine manufacturers and maintenance service providers around the world to restore the material aesthetics and efficiency. Though there are number of cleaning chemistry which could successfully remove these contamination's from the surface, major shortcomings like processing time, disposal (some solvents and chemicals are toxic and not environmental friendly, requires special disposal procedures), user's health & safety and efficiency in cleaning the complex geometries and large parts makes the manufacturers and maintenance service providers to look for alternative cleaning methods. In this paper, some of the commercially available alternative cleaning methods are discussed along with their working principle, capabilities, applications, advantages and disadvantages. Keywords—Scale and oxide removal, jet engine alloys, alternative cleaning methods.
Carbonaceous deposits of diesel engine piston are known to reduce engine durability and performan... more Carbonaceous deposits of diesel engine piston are known to reduce engine durability and performance. Little research has been conducted on the deposits removal by laser technique. In this paper, the deposits on the surface of piston crown part before and after laser cleaning were examined by FTIR, XPS and SEM/EDX. The deposits were found to be distributed non-uniformly on the surface and they could be distinguished as a thicker layer of contaminants, located mainly in the plug region, while a thinner layer can be found in the remaining area. The main constituents of the deposits were analyzed as Fe 3 C, Fe 3 O 4 , possibly FeOOH, oxygenated hydrocarbons as well as carboxylates. Laser cleaning can remove Fe 3 C completely, and reduce the concentration of oxygenated hydrocarbons and carboxylates significantly. Fe 2 O 3 , instead of Fe 3 O 4 , was formed on the cleaned region.
Carbon fibrе reinforcеd polymеr (CFRP) compositеs havе found extensivе applications in aerospacе,... more Carbon fibrе reinforcеd polymеr (CFRP) compositеs havе found extensivе applications in aerospacе, automotivе industriеs, sports equipmеnt, etc. due to thеir excellеnt mеchanical propertiеs and high strеngth-to-wеight ratio. Thesе compositеs havе beеn traditionally curеd with autoclavе for yеars. In recеnt timеs, microwavе curing has gainеd considerablе attеntion among the researchеrs and somе organizations due to thеir advantagеs likе enеrgy and spacе saving, reducеd procеssing time, uniform hеating and increasеd procеss control. This papеr presеnts the reviеw of microwavе curing of CFRP compositеs, thеir curе propertiеs and changе in mеchanical propertiеs in comparison to the autoclavе curing. Challengеs associatеd with the microwavе curing of CFRP compositеs are also addressеd.
—The hot section of the aircraft engine (e.g.: stator casing, turbine blades, etc.,) often gets c... more —The hot section of the aircraft engine (e.g.: stator casing, turbine blades, etc.,) often gets contaminated with the scale, soil and dirt during its operation. These contaminations adhere strongly to the surface along with oxide build up due to the very high operating temperatures. It severely affects the performance of the gas turbine engine by decreasing its efficiency. As of now, chemical cleaning is the most widely used method by the engine manufacturers and maintenance service providers around the world to restore the material aesthetics and efficiency. Though there are number of cleaning chemistry which could successfully remove these contamination's from the surface, major shortcomings like processing time, disposal (some solvents and chemicals are toxic and not environmental friendly, requires special disposal procedures), user's health & safety and efficiency in cleaning the complex geometries and large parts makes the manufacturers and maintenance service providers to look for alternative cleaning methods. In this paper, some of the commercially available alternative cleaning methods are discussed along with their working principle, capabilities, applications, advantages and disadvantages. Keywords—Scale and oxide removal, jet engine alloys, alternative cleaning methods.
Carbonaceous deposits of diesel engine piston are known to reduce engine durability and performan... more Carbonaceous deposits of diesel engine piston are known to reduce engine durability and performance. Little research has been conducted on the deposits removal by laser technique. In this paper, the deposits on the surface of piston crown part before and after laser cleaning were examined by FTIR, XPS and SEM/EDX. The deposits were found to be distributed non-uniformly on the surface and they could be distinguished as a thicker layer of contaminants, located mainly in the plug region, while a thinner layer can be found in the remaining area. The main constituents of the deposits were analyzed as Fe 3 C, Fe 3 O 4 , possibly FeOOH, oxygenated hydrocarbons as well as carboxylates. Laser cleaning can remove Fe 3 C completely, and reduce the concentration of oxygenated hydrocarbons and carboxylates significantly. Fe 2 O 3 , instead of Fe 3 O 4 , was formed on the cleaned region.