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
Detailed analysis of the overtaking process
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
Analysis of pool boiling enhancement on large and small-scale extended surfaces
TADEUSZ ORZECHOWSKIThe 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
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.