Cooled efficiency

Free flow. Dobry and Finn [Chem. Eng. Prog., 54, 59 (1958)] used upward flow, stabilized by adding methyl cellulose, polyvinyl alcohol, or dextran to the background solution. Upward flow was also used in the electrode compartments, with cooling efficiency sufficient to keep the main solution within 1°C of entering temperature. 

An important point needs to be re-emphasised, that the cooled efficiency (t )ici with combustion temperature (T = T oi) >s the same as the uncooled efficiency (t )iu at the rotor inlet temperature (T = T n)... 

For the numerical example the cooled efficiency becomes 0.4205, a reduction of 0.0237 from (tj)ru = 0.4442. The extra loss in efficiency for throttling the cooling air from compressor discharge to the appropriate pressure at the LP turbine entry is thus 0.0052 for the numerical example, which is again quite small. 

The cooling efficiency can be determined from the internal heat transfer. If 7bi is considered to be more or less constant, then it may be shown that... 

Experience gives values of f for various geometries, but St is found to be a weak function of Reynolds number, so in practice there is relatively little variation in cooling efficiency (0.6 < tjc[Pg.72]

In the cycle calculations de.scribed below [2], film cooling was as.sumed. Further, as described in Appendix A, various a.s.sumptions were made for the critical constants, as follows. The constant C in Eq. (5.13) was taken as 0.045, and within W, the cooling efficiency tJcooi as 0.7 and the film cooling effectiveness ep as 0.4. All were assumed to be constant over the range of cooling flows considered. 

It is assumed that the temperature of the coolant does not fully reach the temperature of the metal before it leaves the blade, i.e. Tp, < 71,1. Thus, the concept of a cooling efficiency is introduced... 

Figure 9-128. Companson of cooling efficiency of several packing materials in terms of the coefficient of heat transfer K a. Used by permission of Plastics Technical Service, The Dow Chemical Co., Midland Mich, with data added from Fuller, A. L., et al. Chemical Engineering Progress, V. 53, No. 10 (1957) p. 501 all rights reserved.

The furnace areas of WT boilers require the periodic deployment of retractable soot blowers to remove the buildup of soot and combustion products from water-wall tubes to maintain heat transfer and furnace cooling efficiency, as well as to minimize the interference of flue gas pathways. 

A better cooling efficiency of the compound can be achieved by a lower cooling temperature of the mixing chamber and rotors. Tests were done in order to measure the effect of a decreasing cooling temperature on the silanization efficiency. Figure 29.14 shows the effect of this measure in a... 

Figure 3. Feedback cooling in cavity QED Evolution of the mean atomic effective energy, with no cooling (top curve), cooling based on direct feedback of the photocurrent signal (middle), cooling based on feedback with a simple Gaussian state estimator (bottom). Note the improved cooling efficiency in the second case.

REP, a rod of metal or alloy, referred to as a consumable electrode, is rotated at high speed about its longitudinal axis. Simultaneously, it is melted gradually at one of its ends by a heat source, such as an arc, a plasma, or an electron beam, etc. A thin film of the molten metal is detached from the rod end and ejected from the periphery of the rod by centrifugal force, forming spherical droplets. The atomization is conducted in an inert atmosphere, usually argon. Helium may be used to increase arc stability and convective cooling efficiency of droplets. 

EXAMPLE 6.7 Estimate the cooling efficiency, defined by ) cooi =, of a... 

In spite of the usually low cooling efficiencies (see the exercise above), recent experiments have demonstrated an anti-Stokes cooling from room temperature to 77 K within a certain internal volume of Yb + doped fluorochloride and fluoride glasses under high photon irradiances (Fernandez et ai, 2000). Future practical applications of optical cooling of solids include cooling systems for spacecraft electronics and detectors, as well as for superconductive circuits. 

The positive section of the power banks shown in Fig. 14 uses 40 type-N power Mosfet devices which can drive currents of up to 400 A. The same banks mount also 4 type-P devices for the negative section. The number of devices in the negative section is much smaller since the negative side is subject to much smaller power requirements. All 44 devices are mounted, together with their electronic control boards, on four special liquid-cooled, copper heat sinks. These, thanks to the excellent thermal conductivity of copper, combined with a design which maximizes the contact area between the copper and the cooling liquid, makes it possible to reach the requested cooling efficiency. 

During the course of the reaction, stopcock (F) should remain closed except for short periods in order to avoid loss of the volatile oxirane. There is no danger of excess pressure in the closed system as long as trap (D) is cooled efficiently. 

The direct vaporization of refractory metals from wire loops can be accomplished with large, thin-walled reactor vessels. The high cooling efficiency of thin walls and increased distance between vaporization source and cold surface permit efficient heat dissipation, which is necessary with refractory metals, t... 

The increased cooling efficiency of thin-walled reactors also has permitted the use of more volatile substrates in near molar quantities. (l-3 6-7 10-12-rj 2,6,10-Dodecatriene-l,12-diyl)nickel has been prepared in multiple gram quantities by cocondensation of nickel vapor and 1,3-butadiene. This method has provided a clean one-step route to this complex, which was first isolated and identified by Wilke et al.1 as an intermediate in the cyclotrimerization of 1,3-butadiene by nickel catalysts. 

The rate of addition is not critical, for the reaction is not especially exothermic. However, at even slightly elevated temperatures the N,N-dichloroamines may begin to decompose with the formation of undesired products therefore the addition can be carried out as rapidly as desired within the specified temperature range. With a reasonable cooling efficiency this will be... 

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