Applied Engineering Letters

8-15

Authors: T. Skrúcaný, F. Synák, M. Kendra, S. Milojević

The main purpose of the paper is to determine the change in vehicle energy efficiency due to using the air conditioning system. There is a connection between the changes in vehicle energy efficiency and fuel consumption together with time needed for vehicle acceleration. The paper comprises the measurement results performed at stabilized speeds as well as during vehicle acceleration. The final part of the paper outlines the result of calculation of change in vehicle energy efficiency resulting from air conditioning unit used during New European Driving Cycle.

22-30

Authors: G. K. Makrygiannis, D. P. Margaris

The simple geometry configuration of T-junctions and their capability to act as partial phase separators, especially on offshore platforms, made them common pipeline system components in power and process industries. Moreover, in the pursuit of achieving better phase separation by controlling the maldistribution occurred in the component phases of a mixture at the junction, industries often utilise reduced T-junctions. Nevertheless, most of the published data in which industries was based on to adopt the previous configuration was relating on fully horizontal T-junctions with large main pipe diameters although T-junctions are rarely placed in a horizontal position in such industries, whilst the usage of small main pipe diameters could also lead to scaling down their size. In this regard, the present paper aimed to extend the available data by performing numerical analysis and studying both regular and reduced T-junctions with a small main pipe diameter, and upward inclination angles. It was observed that reduced T junctions performed worse in terms of phase separation compared to regular T-junctions for all inlet conditions applied and irrespective of the side arm inclination, whereas in case of regular T-junctions a superior separation performance was ensured for the inclined side arm at 30°.

115-119

Authors: A. Skulić, B. Stojanović, S. Radosavljević, S. Veličković

This paper deals with the analysis of impact of various factors on power loss and efficiency of worm gearing. Factors that significantly affect the power losses are, principally, types of materials of meshed gears and geometry of worm pair, type and viscosity of lubricating oils, input rotational speed, worm shape, loading, temperature, etc. Results of experimental tests of worm gearing efficiency are also presented in the paper. Tests were conducted according to planned experiment schedule on specialized device AT200, where single-stage worm gearboxes with transmission ratio i=18 has been used. During the test stage, oils of different viscosities (ISOVG 220, ISOVG 460 and ISOVG 680) have been used and their impact on efficiency was monitored. The values of efficiency level are determined at different input rotational speeds (circumferential velocity) and output torques (loads).

128-135

Authors: O. Kayode, O. A. Koya

Nigeria is currently experiencing energy deficit in terms of electrification.Development of renewable energy sources such as Sea wave energy may help augment this deficit. This paper set to investigate wave energy potential of the coast of Nigeria. Data required for estimating the wave energy potential of the coastal waters of Nigeria were obtained from WAVEWATCH III© wave generation model. The wave climate data were analyzed using basic statistical analysis such as average, mean, and range. Due to the scarcity of reliable measured wave climate data, an effort was made to investigate the relationship the mean monthly wave power may have with mean monthly rainfall. Establishing a good level of correlation will provide an alternative mean of forecasting wave power for the coastal region. The results show that the mean annual wave power magnitude generally decreases from the west coast (at 10.74 kW/m) to the east coast (at 5.64 kW/m) for the reference points considered. The most energetic months occurs during the rainy season while the least energetic months occur during the dry season. There is a strong positive correlation between mean monthly wave power and mean monthly rainfall at 5% significant level.

88-92

Authors: N. Palić, V. Slavković, Ž. Jovanović, F. Živić, N. Grujović

3D printing is state‐of‐the‐art manufacturing technology. In addition to prototyping, the development of this technology allows the parts produced by this technology to be used as fully functional assemblies. There are different 3D printing technologies (Fused Deposition Modeling, FDM, Selective Laser Sintering, SLS, Stereolithography, SLA and others), and different materials can be used (polymer filaments, polymer and composite powders for sintering, photopolymers). This paper presents the process of design and fabrication of small load bearing structures by FDM and verification of its mechanical properties, by using three‐point bending test. The printing parameters and setup of the three‐point bending test were analysed from aspects of flexural strength and final bending angle that was determined experimentally and by calculation.

98-101

Authors: A. Çakan, Ü. Önen, F. M. Botsalı

This paper presents, system identification based inverse kinematics analysis and control of a multi‐DOF road simulator. Multi‐DOF road simulators are special devices which are widely used to perform road profiles to a vehicle in laboratory environments. In this paper a road simulator mechanism is virtually designed and inverse kinematics analysis is derived without using any mathematical expression. System identification method is used for inverse kinematics analysis and then controlled to perform desired positions of the vehicle wheel center point.

48-54

Authors: T. Skrucany, S. Semanova, S. Milojević, A. Ašonja

Fuel consumption of heavy duty vehicles is caused by actual vehicle resistances acting during the vehicle motion. This paper deals with possibilities to reduce the vehicle aerodynamic resistance, air drag coefficient. This resistance effects the vehicle fuel consumption by higher vehicle velocities at most. There are evaluated actual values of vehicle air drag coefficient, possible devices reducing the air drag and the influence of chosen aerodynamic devices on the drag reduction and fuel consumption reduction.

66-71

Authors: M. Spasic, Dj. Dihovicni

The main objective of this paper is to show the technology to protect computer systems using firewall technology and through the configuration of firewall, construct defence and protection of the database of the mechanical system engaged in the auto industry which create pipe for exhaust systems on cars by using various techniques, tools, methods, and testing of the software of the firewall and anti-virus. For security reasons, it is necessary to create a script file for anti-virus system and firewall, and rules in order to handle with the database when it is updated.

6-18

Authors: M. Arsalan Anwar, S. Manzoor

The influence of a counter-rotating vortical gust pair is numerically investigated on a streamlined laminar flow and forced convection heat transfer around a steadily rotating two-dimensional circular cylinder. Reynolds number is kept to a fixed value of 100 based on cylinder diameter (D). The working fluid used is water having a fixed Prandtl number of 7. The non-dimensional rotation rate is altered within the vortex shedding regime i.e. 0≤α≤1.5 in the steps of 0.25. The numerical results were computed via commercially accessible CFD software package FLUENT®. The governing flow equations are continuity, momentum, and energy equations have been resolved via constant wall temperature (CWT) boundary condition. The numerical outcomes are computed illustrating the variation in the lift coefficient, Strouhal number, average and local Nusselt number, vorticity and temperature contours around the isothermal rotating cylinder. The influence of the vortical gust is observed to stretch the shear layer in a typical manner. The vortical gust can be treated as an additional heat transfer suppression technique in conjunction with rotation for a circular cylinder.

24-32

Authors: D. Kiran Prasad, K. Venkata Ramana, N. Mohan Rao

This paper presents weight function approach with piece wise polynomial interpolation function to determine the stress intensity factors at the surface and deepest points of a semi elliptical crack induced at the blade mounting locations of the rotor system. Initially, the mathematical model representing tapered rotating disc is solved and the equations for radial stress are obtained. Using the compatibility conditions, these equations are applied to plot the stress distribution at blade mounting locations in steam turbine rotor system. In the second part, weight functions with five and six terms are derived separately at the surface and the deepest points of semi elliptical crack to determine the stress intensity factors. The coefficients of these functions are determined assuming piece wise polynomial stress distribution along the crack. This weight function approach is applied to a semi elliptical crack at blade mounting locations by considering the stresses at discrete points of the crack obtained in first part and the stress intensity factors (SIFs) are determined. The results obtained are validated with the influence coefficient approach.