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Open access

František Dzianik, Štefan Gužela and Eva Puškášová

Abstract

The paper presents a comparison of the process properties of two types of the heat exchangers designed for the heat removal from a high temperature helium cooling loop with steady natural circulation of helium. The first considered heat exchanger is a shell and tube heat exchanger with U-tubes and the other one is a helical coil heat exchanger. Using the thermal and hydrodynamic process calculations, the thermal performance of the two alternative heat exchangers are determined, as well as the pressure drops of flowing fluids in their workspaces. The calculations have been done for several defined operating conditions of two considered types of heat exchangers. The operating conditions of heat exchangers correspond to the certain helium flow rates.

Open access

De Dwaipayan, Nandi Titas and Bandyopadhyay Asish

Abstract

In 21st century, it has been observed that Wire Cut Electrical Discharge Machining (WEDM) has evolved as one of the most important non-traditional machining process. The popularity and its success lies because of its uniqueness towards producing different components which are very difficult to machine like titanium, tungsten carbide, Inconel materials etc and provides a platform in producing intricate complex shape which in many cases become impossible to machine by traditional machining methods. Pure sintered titanium bears very high specific strength, abrasion and corrosion resistances and thus machining this type of materials by conventional techniques becomes very difficult though this material finds immense applications in bio-plant and aerospace components. In the present work, WEDM on pure sintered titanium is studied. The different input parameters of WEDM like, pulse on time, pulse off time, wire tension and wire feed have been varied to investigate the output response like MRR, Surface Roughness (Ra), Kerf Width and Over Cut. A response surface methodology (4 factors 3 level) design of experiment (DOE) has been applied in this context to examine the machining ability of pure sintered titanium and results are found to be satisfactory and verified by confirmatory test. The machining parameters like pulse on time, pulse off time, wire tension and wire feed shows immense effect on the output responses and present study provide an optimal conditions of these input parameters to get the best output responses through RSM

Open access

Michael Welch

Abstract

The purpose of this paper is to present a paradigm, or guide, to the analysis of preloaded bolted joints made using multiple bolts. Classical analysis methods are applied to the interaction of the joint elements subjected to combinations of both in-plane and out-of-plane loads and moments. The distribution of the external loads and moments within the preloaded joint is determined in relationship to individual bolts. An analysis of loads and stresses in individual bolts and dowels along with flange bending and thread shear in tapped or threaded holes is developed. The article brings together a number of concepts and links them into a practical design analysis process that is applicable for many cases of preloaded bolted joints and are adequate to demonstrate the structural integrity of each element of the joint. Interpretation of results, within the context of design standards, is provided. In some cases finite element methods may be more appropriate, and the methods discussed can be used in the validation process.

Open access

M. M. Vishwanath, N. Lakshamanaswamy and G. K. Ramesh

Abstract

Fiction Stir welding (FSW) a unique type of metal joining process in solid state, where the heat generation takes place due to the friction action between the rotating tool and the work piece. It is generally used to join all series of Aluminum alloys with good strength and other metallic alloys finds difficult to weld through regular fusion welding techniques. The metal joining takes place in the solid state as the metal to be welded reaches about 80% to 90% of its melting temperature. The joining of metals in friction stir welding does not require any filler metals all classes of Aluminium alloys can be joined and in some desirable cases dissimilar metal compositions and Aluminiun metals composites can be joined satisfactorily. Joining of dissimilar metals has become a trend in the industries like aerospace, automotive chemical etc. as the helps in reducing the cost incurred by eliminating the costly materials. In the present study an experimental investigations are made to study the heat transfer behavior by determining the temperature distribution in AA5052-AA6061 plates during the Friction Stir welding. A three dimensional transient analysis is made by using ANSYS finite element analysis software. Thermocouples are placed at the suitable locations and the same point the temperature readings were taken from the simulation results. The experimental data is compared with the numerically simulated results. The numerical simulations results obtained are in better agreement with the experimental data obtained.

Open access

Lyubomyr Poberezhny, Andrij Hrytsanchuk, Igor Okipnyi, Liubov Poberezhna, Andrij Stanetsky and Nadiya Fedchyshyn

Abstract

The processes of supplying natural gas are accompanied by significant losses. In this regard, the complex problem of minimizing losses and improving the efficiency of energy use is very relevant. Steel pipelines for transportation of oil and gas often cross the tracks or are located parallel to the lines of electric power transmission lines of alternating current. Most dangerous from the corrosive point of view of the combination of the chemical composition of the soil electrolyte and the vagal current density were established.

Open access

Mykhailo Student, Andriy Vojtovych, Hanna Pokhmurska, Olena Maruschak, Oleksandra Student and Pavlo Maruschak

Abstract

A wear proof layer was obtained by applying vibration with a frequency of 100 Hz and amplitude of 0; 70; 300 μm to the cored wire of Fe-Cr-B-C doping system during welding. It was shown that horizontal vibration affects the grinding process of boride inclusions: their average diameter reduces from 175 to 5 μm, and the amount of (FeCr)2B plastic phases increases during the redistribution of phases. Wear resistance of the metal, which was deposited using horizontal vibration with an amplitude of 300 μm, increases by 2.3-2.5 times due to wear with the fixed and unfixed abrasive material, and by 2.8 times due to wear under impact loads. For restoration and strengthening of large-size parts, it is proposed to add Al-Mg powder (Al = 47 - 53 %, Mg = 53-47% wt. %) to the CW charge to increase wear resistance of the deposited metal of the Fe-Cr-B-C system. This contributes to the dispersion of the boride inclusions, the average diameter of which decreases from 70 to 5 μm. In the structure of the deposited metal of the Fe-Cr-B-C system, inclusions of the complex alloyed nitrides are extricated with an average size less than 1.0 μm. As a result, the average value of microhardness increases from 700 to 900 HV. Wear resistance of the deposited metal increases by 1.5 times due to wear with the fixed and unfixed abrasive material, and by 2.0 times due to wear under impact loads.

Open access

Juraj Kabát, Štefan Gužela and Peter Peciar

Abstract

The aim of this work is to investigate a heat performance of a Multi-Layered Oscillating Heat Pipes Heat Exchanger (ML-OHPHE) for the application of heat recovery in heating, ventilation and air conditioning systems (HVAC systems). The heat exchanger is investigated experimentally under different conditions of heat loads and filling ratios. The experimental data results are compared to the data obtained from Honeywell’s UniSim® Design Suite software. In the end the NTU analysis of the ML-OHPHE is done and a value of overall heat transfer coefficient is calculated. The results of the experiments indicate that the ML-OHPHE could serve as a completely passive heat transfer device in the application of heat recovery in HVAC systems.

Open access

Veldurthi Naresh, D. Bodas, Chandel Sunil and Bhave Tejashree

Abstract

In the present work, two geometrically similar passive geometries with dumbbell shape were designed to perturb the dominating viscous forces in the low Reynolds number (Re) flows of the fluids. The geometries were designated as PDM-I and PDM-II, in which all the linear dimensions were related by a constant scale factor of two. Mixing efficiencies and pressure drops of the species at various Reynolds number (Re) were calculated to estimate the scaling effect validations. Finally, the geometrically similar PDM geometries were fabricated in Polydimethylsiloxane (PDMS) polymer to evaluate the scaling effect on the mixing efficiencies of the dyes and validated with the simulation results of species mixing.

Open access

Bhosetty Keerthana, Gurram Vijaya Kumar and Kumba Anand Babu

Abstract

Minimum Quantity Lubrication has enormous influence on the process parameters in machining. The main aim of the present work is to study the effects of spindle speed, depth of cut, tool material, amount of coolant dispensed and type of coolant on surface roughness and tool temperature in EN31 steel die making including Minimum Quantity Lubrication (MQL) by introducing a self-designed MQL setup and to optimize the responses using fuzzy-logic and Particle Swarm Optimization technique.

Open access

Peter Šlesar and Roland Jančo

Abstract

The aim of the article is to point out the sealing efficiency of the two-language seal of the water pump bearing when radially deflecting the shaft within radial clearance. In order to obtain a radial displacement of the shaft at a location under a two-language seal, dynamic bearing simulation was performed using the MSC Adams program. The largest radial deviation of the shaft was applied in final seal analysis where the contact pressure changes on the individual tongues of the seal were recorded.