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61.
62.
液锻连挤硅线石粒子/铝复合材料的摩擦磨损行为 总被引:2,自引:0,他引:2
采用液锻连挤成形工艺获得了一种新型硅线石颗粒增强LY12铝基复合材料,其性能可与常规热挤压件媲美.摩擦磨损性能测试表明:硅线石颗粒增强铝基复合材料具有优良的摩擦磨损性能,且其耐磨性能随粒子体积分数增加而增加.材料经液锻连挤后,硅线石粒子在强大三向压应力作用下嵌镶于基体内,粒子很难拉脱,承受摩擦力的作用时,硅线石粒子起支承作用,粒子硬度高,故使复合材料整体耐磨性能提高. 相似文献
63.
64.
Transport phenomena studies on single phase “model” fluids are of limited value in biochemical engineering if they cannot be translated to the heterogeneous systems encountered in real fermentation processes. In this paper we discuss the utility of polymer solutions as models of filamentous fermentation broths for evaluation of: pipeline friction factors and impeller power numbers (turbine and helical ribbon). To a first approximation, polymer solutions can serve as suitable models for the prediction of laminar flow pressure drop in pipelines and turbulent power consumption in stirred tanks. However, results obtained on polymer solutions do not directly apply to filamentous fermentation broths for predictions of laminar flow impeller power consumption and the transition point for turbulent flow in stirred tanks. These discrepancies are believed to result from the existence of a time dependent yield stress in filamentous fermentation broths. 相似文献
65.
New experimental results on pressure loss for the single and two‐phase gas‐liquid flow with non‐Newtonian liquids in helical coils are reported. For a constant value of the curvature ratio, the value of the helix angle of the coils is varied from 2.56° to 9.37°. For single phase flow, the effect of helix angle on pressure loss is found to be negligible in laminar flow regime but pressure loss increases with the increasing value of helix angle in turbulent flow conditions. On the other hand, for the two‐phase flow, the well‐known Lockhart‐Martinelli method correlates the present results for all values of helix angle (2.56‐9.37°) satisfactorily under turbulent/laminar and turbulent/turbulent conditions over the following ranges of variables as: 0.57 ≤ n′ ≤ 1; Re′ < 4000; Rel < 4000; Reg < 8000; 8 ≤ x ≤ 1000 and 0.2 ≤ De′ ≤ 1000. 相似文献
66.
用真空浸渍法成功制备出了超高分子量聚乙烯纤维/有机玻璃(UHMWPE/PMMA)复合材料,并对基体材料PMMA,单向超高分子量聚乙烯纤雏/有机玻璃复合材料以及三维编织超高分子量聚乙烯纤维/有机玻璃(即UHMWPE3D/PMMA)复合材料的摩擦磨损性能进行了研究。实验证明UHMWPE/PMMA复合材料具有优良的摩擦磨损性能。经过纤维增强的复合材料的摩擦磨损性能优于基体材料,三维编织纤维增强的复合材料其磨损远小于单向纤维增强的复合材料,但其摩擦系数没有显著变化。 相似文献
67.
几种工程塑料摩擦磨损性能的分析与比较 总被引:3,自引:0,他引:3
对聚甲醛,尼龙1010和聚四氟乙烯三种工程塑料的摩擦磨损性能进行了测试,分析和比较了它们不同截荷及不同对磨时间的摩擦磨损性能。 相似文献
68.
Todd?L.?KurthEmail author Girma?Biresaw Atanu?Adhvaryu 《Journal of the American Oil Chemists' Society》2005,82(4):293-299
The frictional behaviors of methyl oleate (MO), methyl palmitate (MP), methyl laurate (ML), and methyl stearate (MSt) as additives
in hexadecane have been examined in a boundary lubrication test regime using steel contacts. It was found that the transient
attributes of coefficient of friction (COF)-time spectra are a sensitive measure of adsorption equilibria. Critical additive
concentrations were defined and used to perform novel and simple Langmuir analyses that provide an order of adsoprtion energies:
MSt>MP>MO≥ML. Application of Langmuir, Temkin, and Frumkin-Fowler-Guggenheim adsorption models via nonlinear fitting of a general cooperative model demonstrates the necessary inclusion of cooperative effects in the applied
model. In agreement with the qualitative features of steady-state COF-concentration plots, MSt modeling requires minimal cooperative
interaction terms. However, MO, MP, and ML data require large attractive interaction terms to be adequately fitted. Primary
adsorption energies calculated via the cooperative model are necessarily decreased, whereas total adsorption energies correlate well with values obtained via critical concentration analyses. These results and comparisons with previous adsorption studies of MO and MSt suggest that
primary (ester-surface) and secondary (alkyl-surface) adsorbate-adsorbent, adsorbate-adsorbare, and (free-additive) adsorpt-adsorpt
interactions collectively determine both the calculated primary and the cooperative interaction energies. 相似文献
69.
The rheological behaviors of high‐impact polystyrene (HIPS) and HIPS/TiO2 composites were investigated by use of a rheometer in the present article. HIPS exhibited a constant critical stress of the sharkskin in various temperatures, and the analysis indicated that the mechanism of sharkskin of HIPS was wall–slip and its special temperature dependency was determined by weak wall–melt adsorption. The experimental results also showed that the introduction of TiO2 into HIPS only slightly influenced the apparent viscosity (ηa) of the composites. Moreover, TiO2 exhibited an unusual effect on the non‐Newtonian index of the composites at high shear rate. Both phenomena indicated the increase of inner free volume induced by TiO2 in molecularly rigid HIPS. Moreover, it was noteworthy that a featured stress could be used to label the dispersion of TiO2 in the HIPS matrix, and the numeric affinity of this featured stress and the critical stress of sharkskin revealed that both processes were relevant to the same molecular relaxation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 802–807, 2005 相似文献
70.