Contents of Journal of Mechanical Engineering 53, 1 (2003) 


 

P. GILLIERON: Detailed analysis of the overtaking process                  1

P. LIU, J. LI, Y. C. TSE, Ch. LU, K. P. QUEK, G. R. LIU: Heat 
treatment analysis of sprocket                                            17

T. ORZECHOWSKI: Analysis of pool boiling enhancement on large 
and small-scale extended surfaces                                         38

O. KROPAC, P. MUCKA: Relations between characteristics 
of longitudinal unevenness of roads: a review                             49

Abstracts



Detailed analysis of the overtaking process

PATRICK GILLIERON

The work presented in this paper proposes to characterize an overtaking process involving two vehicles by analyzing the aerodynamic coefficients of drag, side-forces and yaw. The analysis is based on a simplified motor-vehicle geometry (hatchback) and a RANS type numerical approach with a turbulence model and a wall law. The overtaking process, considered as a continuous evolution of stationary states, is first analyzed for straight trajectories, with and without crosswind. The dimensionless results are compared with the results obtained on an isolated vehicle subjected to crosswind.

Heat treatment analysis of sprocket

PING LIU, JING LI, YU C. TSE, CHUN LU, KWANG P. QUEK, GUI R. LIU

The entire heat treatment process, including induction heating followed by oil quenching, for sprockets made of S45C mid-carbon steel is systematically analysed. To study the effect due to different sprocket cutout dimensions and positions, the finite element method is implemented and coupled thermal and structural analysis is performed. Phase transformation and temperature dependent material properties are incorporated in the simulation. The key steps of the simulation are to fit the proper heat flux induced in induction heating and the mechanical material properties at high temperature. The simulated temperature distribution and distortion of sprockets have been investigated, and the results show a good agreement with the experimental results.

Analysis of pool boiling enhancement on large and small-scale extended surfaces

TADEUSZ ORZECHOWSKI

The work discusses problems of heat exchange intensification at boiling using the technique of small-scale surface extension. The general form of a one-dimensional equation of the temperature distribution is given for a fin covered with a microstructure, whose stochastic parameters and properties define a multi-dimensional quantitative distribution function. The solution of the equation is provided for an extended surface prepared by applying the technology of mechanical punching. Tests of such a structure were carried out in water at ambient pressure. The temperature distribution measured with a thermovision camera was used for the numerical analysis of the problem. The investigation results confirm the theoretical analysis for a fin with a microstructure.

OLDRICH KROPAC, PETER MUCKA

Four indicators of longitudinal unevenness of roads are considered: double-amplitude, International Roughness Index (IRI), wavelength band indices, and the power spectral density (PSD) of the unevenness. Parameters C and w of the last-named function are used as basic indicators, to which all remaining ones are compared. Special attention is paid, based on a simulation study, to the relation between IRI and PSD parameter C extended to also include the waviness w.