Axial void fraction profiles in subcooled flow boiling in a vertical annulus were obtained using gamma attenuation techniques for different levels of mass flux, wall heat flux and inlet subcooling. A mechanistic model was developed to predict the axial void fraction profile. Various closure relationships were used and a new model, for dividing the wall heat flux between vapour generation and heating the subcooled liquid, was incorporated.

The performance of multi-stage flash, MSF, desalination system is studied during the design stage. Effects of number of stages, top brine temperature and feed-desalinated water ratio on MSF system operating limits, coefficient of performance and system size are investigated, In addition, the investigation is extended to study the effect of the variation of the operation conditions due to weather changing on the performance and production of an existing MSF system 

An analysis is presented for fully developed laminar convective heat transfer in a pipe provided with internal longitudinal fins, and with uniform outside wall temperature. The fins are arranged in two groups of different heights. The governing equations have been solved numerically to obtain the velocity and temperature distributions. The results obtained for different pipe-fins geometries show that the fin heights affect greatly flow and heat transfer characteristics. Reducing the height of one fin group decreases the friction coefficient significantly.

Fully developed laminar convective heat transfer in a partially heated pipe was investigated. The tube was assumed to be heated along a peripheral angle eh while the rest of its surface was assumed to be adiabatic. Two different heating conditions were investigated; uniform temperature and uniform heat flux along the heated surface. The governing equations have been solved numerically using finite volume technique to obtain the temperature distribution and heat transfer coefficient represented by Nusselt number.

Natural convection from a vertical plate enclosed in a horizontal cylinder was investigated numerically using finite element technique together with SIMPLER algorithm. Enclosure geometric configurations of L/Do = 0.25, 0.5 and 0.75, and Do = 0.1, 0.2 and 0.3 m were investigated. Laminar conditions up to Rayleigh number RaL of 3×107 were investigated. Flow fields represented by stream lines, velocity vectors and isothermal lines were presented for various conditions.

Natural convection in horizontal cylindrical annuli was investigated numerically using finite
element technique together with SIMPLER algorithm. Annulus geometric configurations of
Do/Di = 2, 3, 4 and 5 were investigated. Laminar conditions up to Rayleigh number Rai of 105
 were investigated. Flow fields represented by stream lines, velocity vectors and isothermal
lines were presented for various conditions. The data of heat transfer, represented by Nusselt
number Nui and effective thermal conductivity ratio ke/k were presented versus Rayleigh

Two-dimensional laminar natural-convection heat transfer in air around horizontal ducts with rectangular and square cross sections is studied numerically. Different aspect ratios are used for wide ranges of Rayleigh numbers. Results are presented in the form of streamlines and isothermal plots around the circumference of the ducts. The computational procedure is based on the finite-element technique. Temperature and velocity profiles are obtained near each surface of the ducts. Reverse flow and circulations are observed at high aspect ratios.