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Full-Text Articles in Engineering

Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang Aug 2004

Numerical Modeling For Atomization Of Coaxial Liquid/Gas Jets, Stephen Gen-Ken Chuech, Andrzej J. Przekwas, Chih-Yuan Wang

Journal of Marine Science and Technology

In the present study, the atomization of a coaxial injector in the liquid/gas engine combustor was numerically investigated. Based on the wave instability analysis of the interface between liquid and gas, an atomization model for the high-speed liquid jets was established by coupling with the jet flow solutions. First, the wave instability was analyzed to predict the growth rates along the liquid jet surface by numerically solving the wave dispersion equation, while the governing equations of the liquid flow were solved for the formation of the liquid jet core and the variation of the liquid flow structure. Then, these two …


Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu Aug 2004

Steady-State Performance Of Wide Parabolic-Shaped Slider Bearings With A Couple Stress Fluid, Jaw-Ren Lin, Yu-Ming Lu

Journal of Marine Science and Technology

According to the Stokes micro-continuum theory, the effects of couple stresses upon the steady-state performance of wide parabolicshaped slider bearings are presented in this paper. To account for the couple stress effects arising from a Newtonian lubricant blended with various additives, the modified non-Newtonian Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. Comparing with the traditional Newtonianlubricant case, the effects of couple stresses characterized by the couple stress parameter signify an improvement in the steady-state performance. Increasing values of the couple stress parameter increases the bearing load-carrying capacity and reduces the required volume flow …


Analysis Of Dynamic Characteristics For Wide Slider Bearings With An Exponential Film Profile, Jaw-Ren Lin, Chi-Ren Hung Jun 2004

Analysis Of Dynamic Characteristics For Wide Slider Bearings With An Exponential Film Profile, Jaw-Ren Lin, Chi-Ren Hung

Journal of Marine Science and Technology

Analysis of dynamic characteristics plays an important role in designing hydrodynamic bearings. Based upon the thin-film lubrication theory, the analysis of dynamic characteristics for a wide slider with exponential film profiles is presented when taking into account the bearing squeezing action. By applying a small perturbation technique to the dynamic Reynolds-type equation, both of the steadystate performance and the dynamic characteristics are then evaluated. Comparing with those of slider bearings with an inclined-plane film shape, higher values of the load-carrying capacity, stiffness coefficient and damping coefficient are predicted for the bearing with larger values of the inlet-outlet film ratio. These …


Application Of Genetic Algorithm To The Shape Optimization Of A Constrained Double-Chamber Muffler With Extended Tubes, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu Jun 2004

Application Of Genetic Algorithm To The Shape Optimization Of A Constrained Double-Chamber Muffler With Extended Tubes, Long-Jyi Yeh, Ying-Chun Chang, Min-Chie Chiu

Journal of Marine Science and Technology

As the compact design of a muffler system within a constrained environment of a existing machine room becomes obligatory, it also becomes essential to maximize the acoustic performance of mufflers under space constraints. In this paper, the shape optimization of a double-chamber muffler with an extended tube is presented. The main characteristic of the solution methodology is the use of genetic algorithm (GA) as the optimizer. In the paper, the acoustic performance of sound transmission loss (STL) derived by transfer matrix is conjugated with the techniques of GA searching. A numerical case of noise elimination in full band noise is …


Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai Apr 2004

Numerical Optimization Of Sound Absorption Systems With Constrained Single-Layer Absorber, Ying-Chun Chang, Long-Jyi Yeh, Min-Chie Chiu, Gaung-Jer Lai

Journal of Marine Science and Technology

The thickness and the attached area of the sound absorber are confined in the practical engineering design while the sound absorber is applied inside the machine room to eliminate the reverberant sound energy. The optimization of the shape of the absorber and the quantification of the exact area of the absorber (in order to meet the required value of sound pressure level (SPL) at the concerned receiving point) becomes essential. For purposes stated above, two powerful gradient techniques with a logical control algorithm are applied during the optimization of the sound absorption system. Both the optimization of shape and the …


Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee Apr 2004

Coupled Problem Of Thermoelasticity For Multilayered Spheres With Time-Dependent Boundary Conditions, Zong-Yi Lee

Journal of Marine Science and Technology

This paper deals with quasi-static coupled thermoelastic problems for multilayered spheres. Using the Laplace transform with respect to time, the general solutions of the governing equations are obtained in transform domain. The solution is obtained by using the matrix similarity transformation and inverse Laplace transform. We obtain solutions for the temperature and thermal deformation distributions for a transient state. It is demonstrated that the computational procedures established in this paper are capable of solving the generalized thermoelasticity problem of multilayered spheres.


Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu Apr 2004

Effects Of Viscous Shear Stresses On The Squeeze Films Of Porous Parallel Rectangular Plates, Jaw-Ren Lin, Long-Jin Liang, Rong-Fang Lu

Journal of Marine Science and Technology

Considering the effects of viscous shear stresses, a study of squeeze-film behavior between porous parallel plates with finite width is presented. Based upon the Brinkman model (BM), two general coupled Reynolds equations derived for curved surfaces [20] are applied to predict the two-dimensional squeeze-film pressure and thereafter the squeeze-film characteristics. The results show that the BM predicts quite different squeeze-film behaviors to those obtained by using the slip-flow model (SFM) and the Darcy model (DM). Comparing with the SFM, the viscous shear effects provide an increase in the load-carrying capacity and lengthen the response time of finite porous squeeze-film plates. …


The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung Apr 2004

The Effects Of Couple Stresses In The Squeeze Film Characteristics Between A Cylinder And A Plane Surface, Jaw-Ren Lin, Won-Hsion Liao, Chi-Ren Hung

Journal of Marine Science and Technology

On the basis of the Stokes micro-continuum theory, the effects of couple stresses resulting from the lubricant blended with various additives upon the squeeze film behavior between a long cylinder and a plane surface are analyzed. Compared to the conventional Newtonianlubricant case, the couple stress effects characterized by the couple stress parameter signify an improvement in the squeeze film characteristics. Increasing values of the couple stress parameter increases the hydrodynamic load-carrying capacity and provides a longer time to prevent cylinder-plane surface contact. The approaching time of the cylinder in reducing the film thickness h m * = 1 to h …


Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee Feb 2004

Unveiling The Crucial Role Of Impact Nergy Loss For So-Called Incompressible Fluid Flow, Jiunn-Shean Chiang, Shu-Hao Chuang, Hsing-Juin Lee

Journal of Marine Science and Technology

Experiments show that pipe flows with large expansion angle and area ratio always accompany with significant amount of energy loss, actually energy loss ratios over 70% of incoming flow kinetic energy are commonplace. It is generally believed that all the energy loss is entirely due to viscous dissipation effect. In this paper, several interesting demonstrations have been given to prove the existence and importance of impact energy loss. Literally, impact energy loss is usually more important than viscous energy loss in many cases. In fact, the pipe expansion flow can be configured as high-speed flow ramming into low-speed flow and …