Speed, loading, effect

FIGURE 26.21 Coefficient of friction (A) and the temperature rise (B) in the contact area between a natural rubber (NR) gum compound and a thermocouple slider as function of speed at different loads. Also shown are the data when plotted against log a v (C), indicating a rising portion of a single master curve which absorbs also the apparent load effect. 

The mass-loading effect of a gas was evaluated in a room-temperature pressure cell filled with helium (whose speed of sound, Vf, is 965 m/s at 0°C) at from 1 to 4 atmospheres gauge (Figure 3.47). A linear dependence of velocity on gas density was observed, as expected [62]. The discrepancy between calculated and measured values was thought to be due to insufficient thermal equilibration between measurements. In this application of the FPW device, there is no differ-... 

Figure 10.15. Solids loading effect on just suspended speed from Chowdhury (1997) and Penney et al. (1997).

The ratio diss/f is about 0.3-0.5 therefore, the direct dependence of the dissociation rate coefficient on electron temperature is not significant. Assuming that atom formation is due to the dissociation of molecules and atom losses are due to vacuum pumping with speed Sp (the loading effect is discussed next), the kinetic balance equation for atomic oxygen density o can be presented as... 

The power factor is also an important factor to consider. The power factor of the DC drive reduces slightly with load, but it drops drastically with speed. This becomes more severe as the horsepower increases. The power factor of the variable frequency AC drive is higher than the power factor of the DC drive and it is much less affected by speed. In fact, for small to medium horsepower variable frequency AC drives, the power factor is essentially independent of load and speed. The effect of the power factor on overall energy cost cannot be simply calculated by multiplying the line-to-shaft efficiency with the power factor. 

The effect of Incorporating the Reynolds rupture boundary condition upon load capacity, other paramters remaining fixed, may be seen from Figures 3 and 4. As would be expected there is an enhancement of load capacity In comparison with the value determined with the half-Sommerfeld boundary condition. The formulae for film thickness with the two rupture conditions (18 and 19) may straightforwardly be rearranged to render expressions with the speed-load parameter as the subject. For the Reynolds condition this is. 

Zhu, D., Elastohydrodynamic Lnbrication in Extended Paranteter Ranges, Part I Speed Effect, Part II Load Effect, to appear in Tribology Transactions. 

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