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CFD study of isothermal flow in an afterburner system

Thu, 01 Dec 2005 00:00:00 GMT

Title: CFD study of isothermal flow in an afterburner system Authors: Ganesan, S; Kumar, S Kishore; Ganesan, V Abstract: This paper focuses a detailed numerical prediction of non-reacting flow analysis in a practical 1/3 scaled model gas turbine afterburner system. The analysis is performed using SIMPLE algorithm in a body-fitted multi-block grid using ST AR-CD software. The turbulence is simulated using standard k-ɛ model. The validation of software is carried out in a afterburner model by comparing axial, radial and circumferential velocities at various axial locations. The agreement between the prediction and experimental data are quite reasonable. The analysis is extended to the flow in a practical afterburner system. The afterburner system consists of an annular diffuser, a complex three-dimensional flame stabilizer, a liner with chute, screech and cooling rings holes and a convergent nozzle. The wall static pressures are compared with experimental data obtained from rig results for both core and bypass casing. The agreement between CFD prediction and experimental data are in close agreement. The predicted length of the re-circulation zone of the lower radial gutter is larger (2.7 times width of the gutter) than upper radial gutter, which is about 2.3 limes width. This is due to combined effect of annular diffuser and lower radial gutter. But the length of the re-circulation zone of the annular ring is slightly less than (0.94 times) the width of the v-gutter. The effect at' different mass flow rates on the afterburner performance is also evaluated and it is observed that mass flow rate does not affect the re-circulation zone characteristics. An increase of 20% in mass flow rate increases the exit nozzle velocity by 35%. Page(s): 487-497

A new design proposal for intelligent routers to avoid congestion in TCP/IP networks

Thu, 01 Dec 2005 00:00:00 GMT

Title: A new design proposal for intelligent routers to avoid congestion in TCP/IP networks Authors: Pujeri, Ramachandra V; Sivanandam, S N Abstract: In this paper, the various methods to detect network congestion and a method to avoid and recover from such congestion are discussed. This is a proposal to embed intelligence within routers, which will enable them to periodically check each of their communication paths for congestion and correspondingly update their router table and heuristic knowledge base. This is done using a new artificial intelligence concept called the software agents. This method provides a level of abstraction thereby minimizing the visible complexity, so that the source and destination can be designed more easily. Page(s): 481-486

Behaviour of slurry infiltrated fibrous concrete (SIFCON) simply supported two-way slabs in flexure

Sat, 01 Oct 2005 00:00:00 GMT

Title: Behaviour of slurry infiltrated fibrous concrete (SIFCON) simply supported two-way slabs in flexure Authors: Rao, H Sudarsana; Ramana, N V Abstract: Slurry infiltrated fibre concrete (SIFCON) is one of the recently developed construction material. SIFCON could be considered as a special type of fibre concrete with high fibre content. The matrix consists of cement slurry or flowing cement mortar. This composite material has already been used for structures subjected to blast loading, repair of pre-stressed concrete beams and safe vaults¹. This paper presents the information on behaviour of two-way slabs in flexure. Flexure and cyclic load tests have been conducted and compared with fibre reinforced concrete (FRC) and plain concrete slabs. Both strength and deflection characteristics have been studied. The results of the experimental investigation indicate that with 12% fibre by volume of matrix slabs possess excellent performance among other slabs in all respects. Page(s): 427-433

Interference effects on wind pressures on low-rise and high-rise square structures in side-by-side arrangement

Sat, 01 Oct 2005 00:00:00 GMT

Title: Interference effects on wind pressures on low-rise and high-rise square structures in side-by-side arrangement Authors: Lakshminarasimhan, J; Gowda, B H Lakshmana; Sivannarayana, Ch Abstract: In this paper, the effects of interference on three-dimensional bluff bodies with square cross-section placed in side-by-side arrangement for a low-rise body and a high-rise body have been investigated experimentally. The extent of interference effects are brought out by varying the spacing between the bodies. The pressure distributions on the surfaces of the bodies are measured to bring out the severity of interference due to another body adjacent to it. The bodies are exposed to an air stream with a velocity profile satisfying the 1/7^th power law. It is seen that the pressure distribution on rear side and interference side is greatly affected for low-rise body when interfered by a high-rise body in close proximity. Page(s): 398-410