Mirghani Ishak Ahmed

Numerical modelling of a multi-stage solar still

Abstract This paper reports the development of a mathematical model to predict the productivity and the thermal characteristics of a multistage solar still with an expansion nozzle and heat recovery in each stage of the still. Furthermore, this model is used to conduct a parametric investigation of the proposed solar still. A cost analysis is performed to shed some light on the potential of utilizing the proposed still for production of drinking water. It was found that making use of an expansion nozzle and heat recovery techniques in the proposed solar still tend to enhance the productivity of the still and the distillation efficiency. The daily solar still productivity can be up to 9 kg/m 2 , and the distillation efficiency is 87%. The unit cost for distilled water of this still is

Efficient Cryogenic Cooling during Machining of Rolled AlSl 4340 Steel

25.6/1000 gallons.

Parametric Study of an Evacuated Multi-Stage Solar Still

Cryogenic cooling is an environmental friendly and effective cooling technology. The present work investigates the role of cryogenic cooling on tool wear at various cutting conditions. An indigenous method of applying cryogenic coolant was developed. Different methods of circulating the liquid nitrogen and vaporizing it inside the tool holder were tried with the objective of lowering down the temperature at the cutting zone. This was achieved through more efficient heat transfer. As-rolled AISI 4340 steel shafts were turned using coated cemented carbide inserts. Results of tool wear show improvement of tool life during cryo-machining as compared to dry machining especially when heavy depths of cut, high feed values and high cutting speeds are employed. The effect of cryogenic cooling was not pronounced at low speeds, small feed and depths of cut.

Intelligent cooling of a telecommunication electronic package

On this work a practical design to utilize the multistage evacuated solar still concept was developed. The mathematical model of the system was developed based on the energy and mass balance equations of the system. The system components were fabricated and the overall system was assembled. A prototype was constructed and tested at outdoor real solar radiation conditions. The experimental results show a significant improvement of the overall productivity relative to other systems.Copyright

CFD thermal analysis of a telecommunication board

A telecommunications electronic package cooling requirement varies significantly with the change of the intensity of data transfer rate. Using the traditional cooling systems is accompanied with a lot of energy losses, because cooling fans operates always at the same constant speed. A fuzzy logic control was implemented to control the cooling process. Thermal analysis was performed to ensure perfect cooling of the electronic package. By implementing the intelligent control, the energy consumption of the cooling system was reduced by more than 50% relative to the traditional cooling systems.

Improving tool life using cryogenic cooling

A telecommunications electronic circuit boards cooling requirements are studied using CFD (computational fluid dynamics). A mathematical model is developed in order to simulate thermal performance, including radiation, conduction and convection heat transfer. A steady state simulation was carried out using Fluent CFD software and the results were compared with full-sized experimental measurements, which were conducted previously.