Heat Transfer in Horizontal Copper Tube Heated by Electric Heating Process

Heat transfer from electrical and electronics component is essential for better performance of that electrical system, The maximum heat transfer from that system results long period durability. In most of the system base provided for equipments are very small and placed in a very complicated position. so heat transfer by forced convection is not easy for that purpose.The heat transfer by natural convection is the familiar technique used in electronics cooling; there is huge group of apparatus that lends itself to natural convection .This category consist of stand-alone correspondence such as modems and small computers having an array of printed circuit boards (PCB) accumulate within an area. Natural convection heat transfer in heated horizontal duct drive away heat from the interior surface is offered. The duct is open-ended and round in cross section. The test section is heated by provision of heating coils, where constant wall heat flux mentioned. Heat transfer experiment is carried out for channel of 50 mm. internal diameter and 4 mm thickness with length 600 mm. Ratios of length to diameter of the channel are taken as L/D = 12. Wall heat fluxes maintained at q// = 300 W/m2 to 3150 W/m2 . A methodical investigational record for the localsteady state natural convection heat transfer activities is obtained. The wall heating condition on local steady-state heat transfer phenomena are studied.The present experimental data is compared with the existing theoretical and experimental results for the cases of vertical smooth tubes.

Validation of Heat Transfer between Theoretical and Experimental from the Internal Surface of Vertical Tubes with Internal Rings Heated by Electrical Heating Coils

The comparison between experimental and theoretical heat transfer inside heated vertical channels that dissipate heat from the internal surface with and without internal rings  is studied. The experimental setup consists of a circular pipe which is heated electrically by providing constant heat flux on the wall. The theoretical and experimental analysis is conducted in several pipes of same diameter but different lengths. The length of the pipe varies from 450 mm to 850 mm. The length to diameter ratios are taken as L/D = 10, 12.22, 15.56, and 18.89. The value of imposed heat flux varies from 250 to 3340 W/m2. The internal ring thickness varies from 4 mm to 8 mm. separation distance between the internal rings varies from 75mm to 300 mm. The theoretical results are compared with experimental data to ascertain numerical accuracy of the method. The effects of L/D ratio, thickness of internal rings and separation distance on the heat transfer performance are studied. The experimental result is compared with theoretical, theoretical results are found by using ANSYS. In this study theoretical result for wall temperature along the height of tube, fluid temperature at exit of tube are compared with experimental data

Design and development of smokeless stove for a sustainable growth

Air pollution has a serious impact on the health of human beings and is a major cause of death worldwide every year. Out of the many sources of air pollution, the smoke generated from household combustion devices is very dangerous due to the incomplete combustion of fuel. Women from rural areas suffer a lot due to this harmful smoke. Diseases like cancer, throat, and lung infection occur in adults and children due to inhalation of this smoke. The traditional chulha used by rural women is operated by using cow dung, straw, and wood, and the air is blown manually by using small metallic pipes. This paper presents the design and development of an innovative stove to maximize flame temperature and minimize air pollution to overcome the health-related issues of rural women. A smokeless stove is presented, in which wood, straw, and cow dung are taken as primary fuel, and superheated steam as a secondary oxidizer for its operation. In this stove, a forced draft is created by the provision of a small fan, which is operated by solar power thus eliminating the need of creating a forced draft manually by the cook which makes this innovative stove superior to the traditional chulha. Owing to the provision of superheated steam, the flame temperature as well as the burning efficiency increases. The cooking time is reduced due to higher flame temperature as compared to the liquefied petroleum gas stove. The main objective of this work is to minimize air pollution and provide a smoke-free environment to the people using such devices as this innovative stove offers complete combustion of fuel. The flame temperature of the designed stove ranges from 595°C to 700°C and its thermal efficiency is 10–17% higher than that of the traditional chulha. The design of this stove is unique, and its maintenance cost is also much less

Influence of Various Surface Treatments on Mechanical, Thermal, Morphological, and Water Absorption Properties of Rattan (Calamus beccarii) Fiber

The goal of this study is to thoroughly comprehend the advantages of rattan (Calamus beccarii) as potential reinforcement in polymeric composites. The influence of various chemical treatments on thermal, morphological, mechanical and water absorption characteristics of natural rattan (RA) stem fiber were investigated. In this research, RA fiber surface was modified through different chemical treatments such as alkalization, bleaching, and benzoylation. The presence of voids and rough surfaces was investigated on SEM micrographs which are due to removal of lignin, wax, and oils from the fiber surface to a large extent. The results obtained from Fourier transform infrared may indicate the presence of cellulose, hemicellulose, and lignin compounds in the case of untreated and treated RA fiber. The increase in tensile strength and Young’s modulus confirms improvement in the mechanical properties of the RA fiber after chemical treatment. It was observed that alkali-treated RA fibers exhibit highest mechanical properties (295.28 MPa tensile strength, 8.23 GPa Young’s modulus). Also, X-ray diffraction analysis gives a higher crystallinity index (62.50%) for treated RA fiber. Thermogravimetric analysis confirms that there was an increase in the thermal stability of the fiber after chemical treatment. Overall results confirm that the RA fiber is appropriate for use as a reinforcing phase in composite materials for prospective engineering semi-structural applications such as roofing sheets, bricks, door panels, furniture panels, interior paneling, storage tanks, and pipelines

Effect of Various Chemical Treatments on Physical, Mechanical, Thermal and Morphological Properties of Calotropis Gigantea Bast Fiber

This paper highlights the chemical surface modifications of Calotropis gigantea (CG) bast fiber for attaining suitable properties as reinforcements in polymeric composites. The effect of chemical modification on its various properties like physical, mechanical, thermal and morphological properties was also discussed in this research. For this purpose the extracted fibers were chemically treated with various chemicals such as sodium hydroxide, potassium permanganate, sodium chlorite and benzoyl chloride. After surface modifications, its density, mechanical property, thermal gravimetry analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and surface morphology were thoroughly investigated. The tensile strength and Young’s modulus of alkali treated CG fiber was found to be 210.39 MPa and 1.77 GPa respectively. The crystallinity index was improved by 25.37% as compared with untreated CG fiber. Finally, it was observed that alkali treated fiber gives better performance and enhances various properties of Calotropis gigantea stem fibers for use as novel reinforcement in composite materials