Spray formation flow rate effects

The APEX system (Element Scientific Inc., Omaha) as an improved Aridus nebulizer was introduced for ICP-MS in 2004 for more effective solution introduction at flow rates from 20-400 p,lmin-1.88 In this solution introduction system (see Figure 5.15), a microflow PFA nebulizer is combined with a heated cyclonic spray chamber followed by cooling of the nebulized aerosol in a condenser loop and using a multipass condenser cooled by a Peltier element. The APEX solution introduction system results in a significant increase of sensitivity (by a factor of ten in comparison to a standard nebulizer spray chamber arrangement) and a decreasing polyatomic formation rate.89... 

Zhivaikin (Z3) has recently published the results of a detailed investigation of the effects of a gas stream on the film thickness for upward cocurrent, downward cocurrent, and countercurrent flow of the phases over a wide range of flow rates. Thus, downward cocurrent flow is little affected by gas velocities up to about 4 m./sec. For gas velocities between 4 m./sec. and the velocity at which spray formation commences (which has been determined experimentally as a function of the flow rates of gas and liquid and their physical properties), the film thickness is given by... 

The influence of design and operating variables on spray formation for pressure swirl atomizers has been well studied (e.g., Effects of fuel pressure and nominal flow rate... 

Top spray systems During top-spray cooling of an overheated core, the wall temperature is usually higher than the Leidenfrost temperature, which causes water to be sputtered away from the wall by violent vapor formation and then pushed upward by the chimney effect of the steam flow generated at lower elevations (as shown in Fig. 4.25). A spray-cooling heat transfer test with BWR bundles was reported by Riedle et al. (1976). They found the dryout heat flux to be a function of spray rate and system pressure. The collapsed level required to keep the bundle at saturation for various pressures compared reasonably well with that in the literature (Duncan and Leonard, 1971 Ogasawara et al., 1973). 

---