Iraqi journal of mechanical and material engineering

The object of this work is to gain insight into gas-liquid slug flow frequency and the slug unit lengths in horizontal circular transparent pipe of 25.4mm inner diameter and 6m length, experiments done at atmospheric condition with air and water as the working fluids. The superficial gas velocity ranged from 3.947 m/s to 6.579 m/s with superficial liquid velocity around 0.986 m/s and 1.974 m/s. The effects of superficial gas velocity, superficial liquid velocity on slug frequency and slug unit lengths were taken into account. However, the essentials of the problem involve the determination of the slug frequency and slug unit length.In this experimental work a video camera system with image processing technique by MATLAB were used to extract the slug frequency and the slug unit lengths, which contain slug body length and Taylor bubble length or film region length. New data for slug frequency and slug unit lengths were found which achieved good agreements with the previous works.

This paper investigates the linear static and modal analysis of helical machined springs theoretically and numerically using the finite element method with the aid of SolidWorks software. A rectangular cross sectional area of a helical spring was studied with different pitch angle, it was found that increasing the pitch angle increases the spring deflection and decreases both the maximum shear stress and the fundamental natural frequency. Two cases were studied for machined spring, one with different pitch angle and the other with different number of spring starts. The machined helical spring showed better results for maximum shear stress and deflection compared with the conventional helical one. With multiple starts machined helical spring, the spring performance can be improved for a great extent. The results showed that SolidWorks software can be used effectively in modeling and analyzing machined spring.

In present work, a unified method for geometric transfer from CAD to CAM program
has been investigated using iterative process. The B-spline objects (curves and surfaces) of
3P
rd
P degree one patch matrix had been derived and formulated using MATLAB program to
construct a computer program for the geometric transfer as a case study. The procedure of
converting the sculpture surfaces from CAD program to CAM program without any
geometrical distortion had been presented. The implementation of transfer data and the
simulation using UGS program during transformation of any complex profile shape from
CAD to CAM program is done without any distortion in final profile in CAM program. It
was found that the results obtained by applying the present method which utilizes a less time
as compared with the other methods are in a good agreement with the experimental results.

In this paper, the combination between Taguchi method and grey relational analysis was
applied as a key solution for multi objective optimization problem in turning of hard metal.
The variable were; cutting speed, feed rate, depth of cut, and tool nose radius. These
parameters were optimized with respect to surface roughness and metal removal rate. The
surface roughness was to be minimized; on the other hand the metal removal rate is to be
maximized. This problem was solved by converting the multi objective optimization to single
objective optimization by applying the grey relational grade analysis. L16 Taguchi
orthogonal array is used in this paper. The confirmation results show that the grey relational
grade analysis is an effective tool to improve the multi quality objective process.

In this research, optimization of turning cutting conditions and prediction of surface roughness has been satisfactorily accomplished. Taguchi method was applied and second – order mathematical model used for prediction has been developed. Standard LR9R Taguchi orthogonal array, S/N ratio through using the quality characteristic ‘the-lower-the-better’, and ANOVA technique were all adopted to determine the optimum cutting parameters and the more significant factor among them. The parameters that have considered are Spindle speed S, feed rate f, and depth of cut a. Nine specimens were machined according to the levels of parameters, and surface roughness (Ra) values were measured three times for each experiment. The optimum conditions obtained were 1200 rpm spindle speed, 0.12 mm/rev feed rate, and 0.7 mm depth of cut. Among them, the more significant factor is feed rate followed by spindle speed and depth of cut respectively. Based on the results of prediction by the second – order model, it can be concluded that it is a very appropriate to predict the surface roughness of high carbon steel. Confirmation results showed that the predicted values and measured values were dramatically close. This indicates that the Taguchi method and multiple regression can be effectively used to optimize and predict the surface roughness such that the coefficient of determination was found to be 99.82 % with average error not exceed 1.12 %.

The objective of this work is to gain insight into liquid-liquid annular flow, twocomponent
Iraqi gasoil-water flow lengths in horizontal circular transparent pipe of 32mm
inner diameter and 6m length, experiments done at atmospheric condition with oil and water
as the working fluids. The flow patterns that appear are classified in flow pattern maps as
functions of either mixture velocity and water cut or superficial velocities. The superficial
water velocity ranged from 1.69 m/s to 3.38 m/s with superficial oil velocity around 0.39
m/s to 1.58 m/s. The effects of superficial water velocity, superficial oil velocity on annular
flow lengths were taken into account. However, the essentials of the problem involve the
determination of the pressure gradient. In this experimental work a video camera \"high speed
camera\" system with image processing technique by MATLAB were used to extract the hold
up for the fluid that being the annular flow. The theoretical study was executed using fluent
program, a modified turbulent diffusion model is adopted. Simulation results show more
physical predictions with respect to the particle deposition process and concentration profile.
New data for hold up lengths were found which achieved good agreements with the previous
works.