摘要:

AbstractThe applications of energy in Colombia, India and Upper Volta, for which an improvement in the situation is the most urgent, are described. to a more limited extent these applications have also been investigated with respect to Niger, Pakistan and Senegal. the technical economic possibilities of achieving these improvements by means of solar energy in the period up to 1985 are discussed. Concerning those cases which offer a reasonable chance of the use of solar energy, the investigation then turns to the kind of co‐operative programmes between industrialized countries and the developing countries being considered which might contribute to putting these opportunities into practice.This study has revealed the following programmes as offering the best possibilities.1. Small thermal electric generators powered by concentrated sunlight at an operating temperature of about 300°C, the principal application being the driving of pumps for irrigation in India and Pakistan.2. Small absorber cooling systems for India and Pakistan.3. Drinking‐water purification for Niger, Pakistan, Senegal and Upper Volta.4. Battery‐charging systems for India and Pakistan.5. Reforestation for firewood production, close to the major towns of the Sahel countries. Furthermore, much importance is found to attach to the improving of the efficiency of c

ISSN:0363-907X    

DOI:10.1002/er.4440020302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe present analysis gives the effects of the thermoelectric currents on the quasi‐one‐dimensional flow of a real gas in a diverging channel. Numerical solutions are obtained for generator and accelerator modes with subsonic and supersonic flows. the variation of current and power density are presented for the special cases of (i) a linearly diverging channel and (ii) a constant velocity channel. It is observed that the rate of change of the transverse current and the power is slower owing to the influence of thermoelectric curre

ISSN:0363-907X    

DOI:10.1002/er.4440020303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of nonideal conditions on the current flow in a MHD generator has been investigated by two‐dimensional analysis in terms of internal resistance, Hall voltage and uniformity of current distribution. In particular, the effects of (a) temperature profile along the Faraday direction in the plasma, (b) current bunching on cathode surfaces due to phenomena like arc spots, and (c) electrical leakage between adjacent electrodes due to finite resistance of the insulator segments are investigated. the results show that cold boundary layers near metallic electrode surfaces tend to relieve current concentration. the optimum resistivity of wedge‐shaped electrodes for obtaining uniform current distribution in the duct has been calculated for various temperature profiles. the results indicate that the internal resistance of a MHD generator strongly depends on the location and size of current bunched spots on cathodes. the fluctuations in the spot size and its location can lead to large fluctuations in power output. the present calculations reveal that the electrical performance of a MHD generator is not adversely affected by current leakage along insulator segments for small insulator conductivit

ISSN:0363-907X    

DOI:10.1002/er.4440020304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe problem of how to extract energy from ocean waves is discussed by analysing theoretically the hydrodynamic properties of a few ideal devices, involving vertical energy absorbing plates. the aim is to find a mechanism with high ideal efficiency, but still simple enough, such that its realization in practice can be economically feasible.The most promising device involves one or more vertical elastic plates situated in the water perpendicular to the incoming waves. About a quarter of a wavelength after the (first) plate there is a stiff vertical construction extending sufficiently deep in the water such that it is rather immobile. It serves as a reflector of the waves. the elastic plate is set in oscillation by the wave motion and this motion is used to extract the energy by applying a braking force. the optimal force field is discussed in some detail, and it is shown that not much of the optimal efficiency is lost by letting the force field simply be proportional to the velocity. the device is also shown to be sensitive to a fairly broad spectrum of wavelengths, and this spectrum can be broadened by adding more swinging plates. In this way efficiencies of 80‐100 per cent are attained in theory over a wavelength spectrum extending over an order of magnitud

ISSN:0363-907X    

DOI:10.1002/er.4440020305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

ISSN:0363-907X    

DOI:10.1002/er.4440020311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY