Informatics Publishing Limited

V. Narendran ¹, Seralathan Sivamani ¹, V. Hariram ¹, M. Gnanaprakash ¹, A. Mohammed Raffiq ², D. Sathish Kumar ³

Affiliations
1 Department of Mechanical Engineering, Hindustan Institute of Technology and Science, Padur - 603103, Tamil Nadu, IN
2 Department of Automobile Engineering, Hindustan Institute of Technology and Science, Padur - 603103, Tamil Nadu, IN
3 Department of Aeronautical Engineering, Hindustan Institute of Technology and Science, Padur - 603103, Tamil Nadu, IN

Abstract

Objectives: This paper deals with the theoretical and numerical analysis of a convective recuperator used to recover waste heat from the stack flue gases and use it to pre heat the air before it is fed into the combustion chamber of an oil fired water tube boiler. Methods/Statistical Analysis: Three different tube diameters are considered in the present study. Theoretical analysis is carried out to determine the efficiency and other parameters of the boiler with and without recuperator. To support the theoretically obtained results on improved boiler performance by pre heating the air using recuperator, numerical simulation studies is carried out. Findings: The study showed that 10” inch (0.254 m) pipe diameter arranged in a 3 x 3 array gave a flow velocity of air at around 15 to 25 m/s. The stack flue gas exit temperature decreased from 200oC to 135.50oC whereas the inlet air temperature after pre heating through the recuperator is found to be 85oC with a rise in temperature of around 50oC. After pre heating the air, the efficiency of the boiler improved from 71.90% to 74.60%. The quantity of furnace oil saved per day is 3.76% with respect to its present consumption level. CFD simulations are carried out using ANSYS CFX. A good agreement is found between the data obtained from simulation and theoretical analysis. Payback period by incorporating the recuperator to the existing boiler is estimated to be 60 working days. Application/ Improvements: Optimized performance improvement of existing boiler used in industries is possible without extensive redesign by recovering waste heat leading to energy conservation.

Keywords

Air, Boiler, Convective Recuperator, Flue Gas, Performance, Pre Heat.

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S. Prabakar ¹, K. Porkumaran ¹, Parag K. Shah ², V. Narendran ²

Affiliations
1 Department of Biomedical Engineering, Dr N.G.P. Institute of Technology, Coimbatore-641 048, IN
2 Department of Paediatric Retina and Ocular Oncology, Aravind Eye Hospitals, Coimbatore 641 014, IN

Abstract

The retinopathy of prematurity (ROP) is an ocular pathological disorder of retinal blood vessels in premature infants and low birth weight infants. The medical professional who is taking care of premature infants should know who is at the risk of this disease and its exact severity stage. It is also important to decide when screening must begin and how often these infants need to be examined as disease progression leads to a more severe stage causing blindness. The contrast stretching method has been utilized to enhance the ROP colour image. Then an automatic isotropic undecimated wavelet transform (IUWT) scheme has been proposed to extract the abnormal retinal blood vessel and measure its width and tortuosity. The ridge formation of this pathological disorder has also been extracted by IUWT. The quantitative measurements of mean diameter, standard deviation, tortuosity, length of retinal blood vessel and ridge have been considered and computed to find the exact severity stage of ROP. The proposed methods for ROP stage screening system have been validated through machine vision techniques. This proposed system improves the optimum time utilization for ophthalmologists; ophthalmic technicians can provide exact ROP stage and deliver better accuracy and sensitivity in diagnosis.

Keywords

Isotropic Undecimated Wavelet Transform, Retina Vessel and Ridge, Retinopathy of Prematurity, Tortuosity.

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