12 R.9tiactoriedceramics (properties, production, applications)

S5lQ5135 The transplrator, a new rvaporatlvr cooler Ernst, G. and Alf, M. J. of Enhanced Heat Transfer, 1995,2, (I), 79-85. Transpirators are light and efficient evaporative coolers which were pro- posed for space-technology, Till now they are constructed with commer- cially available materials. The cooling capacity of single transpirator- elements and of a transpirator-cooler, equipped with nine elements, was determined. On the base of the experimental results, a mathematical model for the calculation of the cooling capacity was developed.

f;;hXr;~tJ Use of coke with dlfferrnt alkali content In a blast

Janx, J. and Mob&em, H. Stahl Eisen, 1994,114, (9). 83-89. (In German)

95105142 Metals, nltrldes and carbides via solar carbotharmal reduction of metal oxldas Murray, J. P. et a& Energy, Jul. 1995. 20, (7). 695-704. The authors have examined the thermodynamics of carbothermic reduction of metal oxides in either nitrogen or argon atmospheres. The reaction is highly endothermic and proceeds at temperatures from 13QQ to 2350 K for the system considered. Explorato a solar furnace using concentrate 7

experimental studies were conducted in solar radiation. The nature of the solid-

phase oroducts was determined by X-ray wwder diffraction. Nitrides were jormed for svstems run in N,: &bide; were formed for NUM in Arz and metals were ibtained from th& oxides in an argon atmosphere. The u& of solar energy as the source of high-temperature process heat offers the possibility of reducing emissions of greenhouse gases and other pollutants to the environment when it replaces the burning of a fuel for process heat.

Discusses the presence of alkalis in blast furnaces which causes heat losses due to evaporation and condensation, drop in capacity due to an increase in stack kas volumq, particle size reduction of raw materials and damage of the bnckwork. Smce German coke has a high alkali content according to international standards, it was replaced for test purposes by low-alkali coke.

aratus for thermal conductlvlty mea-

Outxourhit, A. and Trefny, J. U. 1994, 7, (4). 319-331.

rimental Heat Transfer, Oct.-Dec.

A transient technique for measuring the thermal conductivities of uncon- solidated powders LS described.

95lQ5137 Variable speed control fans for auxlllary ventllatlon In coal mines Pollak, R. and Litter, B. Clue&& 1994, 134 (12), 770-771, 776, 77g- 779. fin German) \ I

Describes how the practical testing of auxiliary ventilation systems with variable-speed fans largely confirmed the anticipated advantage. Compo- nents required for the construction of the system are commercially avada- ble. Such a system always provides the required air flow to the face area, in contrast to auxiliary ventilation fans hitherto used in the coal mining industry.

95105144 graphite

Synthasls of beta-Slalon from coals or natural

Narciso. F. J. et aL, J. Mater. Res.. 1995. 10. (31. 727-735. The synthesis of b&a-&Ion has been ca&ed b& by heat treatment in nitrogen flow of Spanish coals or mineral graphite, both with a high con- tent of mineral matter. The results were compared wtih those obtained with conventional clay/carbon mixtures.

SSlQ5l45 Trends In refractories for progress of Iron and steel maklna lndustrv

Q5lQ5135 Vortex generators for compact heat exchangers Chen, z Naihuo Cailiaq 1994. 28, (6), 309-314. 349. (In Chinese Discusses the trends in refractories for

P d* Iron

Fiebig, M. J. of Enhanced Heat Transfer, 1995, 2, (l), 43-61. regress and demands of worl

and steel making industry. Includes co e oven problems, blast furnace and Compact heat exchangers are characterized by high heat duties per unit volume and high heat transfer coefficients. This implies small hydraulic diameters, low Reynolds numbers and fins. Emphasis is placed on wing- type vortex generators (WVG). They can be used as fins or to modify fins and are easily into

‘p” rated into heat exchangers. Different WVGs are eval-

uated experimental y and numerically with regard to heat transfer cnhance- ment and

P ressure loss. Detailed data are presented for flow structure, local

and globa heat transfer and pressure losses. The high potential of WVGs for compact heat exchangers is shown.

Q5m5139 Welded-plats heat exchanger for coke-oven gas Berti, S. Tecn& Chin, 1994, 14. (2), 56-59. (In Italian) The heat exchanger consists of a series of rectangular grooved plates, aligned to create flow channels alternated with structural contact

p” ints.

Distributed inflow and outflow allows for heat exchange to take p ace in

runner, smelting reduction, ironmaking pro&s, hot iron pretreatment, basic oxygen converter, electric arc furnace and d.c. electric arc furnace, secondary refining vessels, ladle refractories, tundish refractories. alumina clogging in submerged nozzles, near net shape casting, etc.

Utlllzatlon of pyrlts coal wastes from the Jan Katy ZY Lukwinski, L. et al, Przegl. Corn., 1994, 50, (ll), 49-52. (In Polish) Pyrite coal wastes from the Jan Katy mine are tested to determine their suitabiity for the manufacture of ceramic building materials, cspccially

one or very few ste s, which combined with efficient heat exchange makes this type of ex cg anger useful in terms of overall efficiency and maintenance.

bricks.

13 SPACE HEATING AND COOLING

95105147 Accuracy of CFD for pradlctlng pressure losses In HVAC duct flttlnan ._ ____ s_ Shao, L and Riffat, S. B. Applied Energy, 1995, 51, (3). 233-248. The available data from ASHRAE and CIBSE on pressure losses in HVAC duct fittings are of unsatisfactory accuracy and insufficient quantity, which may lead to inaccurate sizing and poor energy efficiencies in air supply systems. This situation is receiving increasing international attention and much effort is bein fluid dynamics (C

spent in its rectification. especially usin

F% p” ). The pa r presents an investigation o the accuracy If

computation

of the CFD approach. It was ound that the combination of the kc model

12 REFRACTORIES/CERAMICS

Properties, Production, Applications

SSlQ514Q ccmbustlon

Developments In partlculab control for coal and the higher order QUICK scheme produces the highest accuracy (with a relative error of 10%). Grid dependency tests showed that a relatively low aid densitv in the strainht sections uostream/downstream of the duct fit-

Soud, Ii. IEACRl78, IEA Coal Research, Gemini House, IO-18 Pubuzy hg is suftcient but a hygher density b the d&t axis direction is rquired Hilt London SW15 6AA, &?SS.W, Apr. 1995. in the section containing the duct fitting.

95105141 Low cost and hlgh wear reslatant spray matarlal of CO-Fe alloy Notomi, A. et aL, Mitsubishi Juko Giho, 1994, 31, (5). 353-356. (In Japanese) The thermal spray of a hard material has the potential to improve the wear resistance of machine parts. Ceramics and cermet, the cost of which is so hieh that the aoolication of these materials to oractical use is limited, can be-used for we’s; resistant spraying. To develo a a lower cost and im wear resistant surav material. SSC-25Cr-Fe a!

roved lov. a low cost met BP oow-

der, was studied es’s candidate for dense coat bi ihe conventional @asma spray process. A test of the heat exchanger tubes of a coal-tired bculer has revealed that the erosion wear rate of the developed sprayed coating is half that of Cr&NiCr cermet coating.

9!i/QSl49 Alr - The ultimata rafrlgerant Wentink, P. Kolrde Msg., Mar. 1995, (3). 32-33. (In Flemish) Describes the official start-up of the TN0 Cycle pilot refrigeration plant in Apeldoom on the 24th January 1995. The project is covered by the JOULE II European Research and Development Programme and is carried out in cooperation with partners from the UK, Germany and Ireland.

95105149 mat ~tarnar

Alr condltlonlng system wlth an Ice tank for thar-

?&iTi??&d Otsuka, 0. Mitsubish Advance, Mat. 1995,70,2-4. Discusses the benefits of an air conditioning system using ice as a thermal storage reservoir. Points out that the daytime cooling load is reduced by as much as 35% during the summer months by producing ice at night.

352 Fuel and Energy Abstracts September 1995