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Professor Adel Sharif

Emeritus Professor
+44 (0)1483 683610
19 BC 02

Academic and research departments

Department of Mechanical Engineering Sciences.


Indicators of esteem

  • Science Business first pan-European Academic Enterprise Award in the category of Energy/Environment, 2008

  • The Muslim News UK award for excellence in Science and Technology, 2007

  • The Royal Society Brian Mercer Award for Innovation in Science and Technology, 2005

My publications


JS Eow, AO Sharif, M Ghadiri (2003)Adaptive finite element analysis of electrostatic interactions: a sphere between two charged walls and two isolated spheres, In: CHEMICAL ENGINEERING AND PROCESSING42(11)PII S0255-pp. 847-856 ELSEVIER SCIENCE SA
M Hamdan, AO Sharif, G Derwish, S Al-Aibi, A Altaee (2015)Draw solutions for Forward Osmosis process: Osmotic pressure of binary and ternary aqueous solutions of magnesium chloride, sodium chloride, sucrose and maltose, In: Journal of Food Engineering155pp. 10-15 Elsevier

The objective of the present work is to investigate the behaviour of binary and ternary aqueous systems, which could be employed in the selection criteria for draw agents (DA) to be used in Forward Osmosis (FO) process applications. In this study the osmotic properties of the selected binary and ternary aqueous solutions of magnesium chloride (MgCl2), sodium chloride (NaCl), sucrose and maltose are investigated. Osmotic pressures were calculated from water activities obtained from measured relative humidity of the solutions of concentrations in the range 0.5-6.0 mol kg-1 at 298.15 K. The osmotic behaviours of the ternary systems were compared with their binary counter parts; the results showed either positive or negative osmotic synergic effects. This could be used besides transport properties for considering the selection of favourable draw agents from those that exhibited positive synergy, i.e. the osmotic pressure of a ternary solution is greater than the sum of the pressures of the corresponding binary solutions. The results showed that the ternary aqueous solutions of MgCl2 + NaCl showed significant positive synergy and therefore are possible suitable candidates as draw solutions, less so were the sugar-electrolyte systems.

AA Merdaw, AO Sharif, GAW Derwish (2010)Water permeability in polymeric membranes, Part II, In: DESALINATION257(1-3)pp. 184-194 ELSEVIER SCIENCE BV

This study is a combination of experimental and theoretical works in an attempt to produce a new useful empirical model for the mass transfer in pressure-driven membrane separation processes. Following on from our previous work in Part I, this part II paper introduces three new permeability models when using aqueous solutions as feed. The Solution-Diffusion Pore-Flow Concentration-Polarization (SDPFCP) model, which is a combination between the Solution-Diffusion Pore-Flow (SDPF) model [1] and the Concentration Polarization (CP) model, is presented. The SDPFCP model examines the CP model to represent the transfer phenomena outside the membrane by merging its effect within the water permeability coefficient. A further development for this model, the SDPFCP+, is obtained by adding an additional resistance to the system in series with the membrane resistance and the CP. The second model shows fair representation of the experimental results. The Solution-Diffusion Pore-Flow Fluid-Resistance (SDPFFR) model is then proposed to provide better representation for the system. The feed solution resistance to water flux, the Fluid Resistance (FR), is suggested to replace the CP and the additional resistance. The latter model shows excellent fitting to the experimental results; it may be useful for development and design applications, when based on experimental data. Crown Copyright (C) 2010 Published by Elsevier By. All rights reserved.

WR Bowen, N Hilal, RW Lovitt, AO Sharif, PM Williams (1997)Atomic force microscope studies of membranes: Force measurement and imaging in electrolyte solutions, In: JOURNAL OF MEMBRANE SCIENCE126(1)pp. 77-89 ELSEVIER SCIENCE BV
HB Mahood, AN Campbell, AO Sharif, Rex Thorpe (2016)Heat Transfer Measurement in a Three-Phase Direct-Contact Condenser under Flooding Conditions, In: Applied Thermal Engineering Elsevier

The transient temperature distribution and volumetric heat transfer coefficient during the 16 inception of flooding in a three-phase bubble type direct contact condenser have been 17 experimentally investigated. The flooding mechanism and the factors affecting the onset of 18 flooding of the three-phase direct contact column are not considered. A short Perspex column 19 of 70 cm total height and 4 cm internal diameter utilising two immiscible fluids was studied. 20 Pentane vapour with initial temperatures of 40°C, 43.5°C and 47.5℃ was the dispersed phase 21 and tap water at a constant temperature (19℃) was the continuous phase. Only 48 cm of the 22 column was used as the active height and different mass flow rates of both phases were used. 23 The experimental results showed that the instantaneous temperature distribution along the 24 direct contact column tends to be uniform when the direct contact column is working under 25 flooding conditions. Furthermore, the volumetric heat transfer coefficient increases as the 26 dispersed mass flow rate is increased towards the flooding limit and remains constant along 27 the column height. In addition, the dispersed phase mass flow rate that leads to flooding 28 increased with increasing mass flow rate of the continuous phase. The initial temperature of 29 the dispersed phase did not have a considerable effect on the flooding inception limit under 30 the present experimental conditions

AO Sharif, M Sanduk, HM Taleb (2010)The date palm and its role in reducing soil salinity and global warming, In: ISHS Acta Horticulturae882pp. 59-64
AH Sulaymon, AO Sharif, TK Al-Shalchi (2011)Effect of tubes bundle electrode on removal of cadmium from simulated wastewaters by electrodeposition, In: JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY86(5)pp. 651-657 WILEY-BLACKWELL
H Mahood, Alasdair Campbell, Rex Thorpe, Adel Sharif (2017)Measuring the overall volumetric heat transfer coefficient in a vapour-liquid-liquid three-phase direct contact heat exchanger, In: Heat Transfer Engineering39(3)pp. 208-216 Taylor & Francis

An experimental investigation of the volumetric heat transfer coefficient in a three-phase direct contact condenser was carried out. A 75-cm long cylindrical Perspex column with a 4 cm diameter was used. Only 48 cm of the column was utilised as the active direct contact condensation height. Pentane vapour at three different initial temperatures (40°C, 43.5°C and 47.5°C), with differing mass flow rates, and tap water at a constant initial temperature (19°C) with five different mass flow rates were employed as the dispersed phase and the continuous phases, respectively. The results showed that the volumetric heat transfer coefficient increased with increasing mass flow rate ratio (variable dispersed phase mass flow rate per constant continuous phase mass flow rate), the continuous phase mass flow rate and holdup ratio. An optimal value of the continuous phase mass flow rate is shown for an individual dispersed phase mass flow rates. This value increases with increasing vapour (dispersed) phase mass flow rate. Furthermore, it was observed that the initial driving temperature difference had no effect on the volumetric heat transfer coefficient. While, the temperature gained by the continuous phase has a considerable effect.

HB Mahood, AO Sharif, Rex Thorpe (2015)Transient volumetric heat transfer coefficient prediction of a three-phase direct contact condenser, In: HEAT AND MASS TRANSFER51(2)pp. 165-170 SPRINGER
AH Sulaymon, AO Sharif, TK Al-Shalchi (2011)Removal of cadmium from simulated wastewaters by electrodeposition on stainless steeel tubes bundle electrode, In: DESALINATION AND WATER TREATMENT29(1-3)pp. 218-226 DESALINATION PUBL
AO Sharif, MH Afshar, J Moghadasi, TJ Williams (2003)The effect of many-body interactions on the electrostatic force on a finite chain of spheres confined in a long charged tube, In: POWDER TECHNOLOGY135pp. 76-81 ELSEVIER SCIENCE SA
Saleh O Alaswad, Sami Al-aibi, Esat Alpay, Adel Sharif (2018)Efficiency of Organic Draw Solutions in a Forward Osmosis Process Using Nano-filtration Flat Sheet Membrane, In: Journal of Chemical Engineering & Process Technology9(1) OMICS International

The aim of this study is to investigate the performance of specific organic osmotic agents, namely, Sucrose draw solution and Glucose draw solution against deionized water in a Forward Osmosis (FO) process using NF flat sheet membrane. The key parameters affecting the FO process studied were: temperature, flow rates of osmotic agent and feed water, and concentration of osmotic agent. The experimental results showed that increasing the concentration of osmotic agents yield lower water flux, recovery percentage and permeability, along with an apparent increase in the specific energy consumption. Although the findings indicated superior performance of Glucose over Sucrose as a better osmotic agent, it has to be emphasized that both organics were ineffective draw solutions against deionized water for the Nano-filtration (TFC-SR2) membrane used in this study and the given operating parameters.

AA Merdaw, AO Sharif, GAW Derwish (2010)Estimation of concentrations in ternary solutions, In: Journal of Food Engineering
A AlHathal Al-Anezi, AO Sharif, MI Sanduk, AR Khan (2013)Potential of membrane distillation - A comprehensive review, In: International Journal of Water7(4)pp. 317-346

Membrane distillation (MD) is a recent and unique separation technology, in use in the process industry. The process of separation in MD involves the simultaneous heat and mass transfer through a hydrophobic semi permeable membrane, using thermal energy. Consequently a separation of the feed solution into two components - the permeate or product and the retentate or the return stream occurs. MD utilises low grade or alternative energy, e.g., solar energy, geothermal energy, etc., as a source and is the most cost effective separation technology. Hence the process has come to acquire the attention and interest of researchers, experimentalists and theoreticians all over the world. This article is a comprehensive review of the prominent research in the field of MD technology, including its basic principle, MD configurations, area of applications, membrane characteristics and modules, experimental studies involving the effect of main operating parameters, MD energy and economic, fouling and long-term performance. Copyright © 2013 Inderscience Enterprises Ltd.

JS Eow, M Ghadiri, AO Sharif (2007)Electro-hydrodynamic separation of aqueous drops from flowing viscous oil, In: JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING55(1-2)pp. 146-155 ELSEVIER SCIENCE BV
WR Bowen, N Hilal, M Jain, RW Lovitt, AO Sharif, CJ Wright (1999)The effects of electrostatic interactions on the rejection of colloids by membrane pores - visualisation and quantification, In: CHEMICAL ENGINEERING SCIENCE54(3)pp. 369-375 PERGAMON-ELSEVIER SCIENCE LTD
Mustafa S. Mahdi, Hameed B. Mahood, Anees A. Khadom, Alasdair N. Campbell, Mohanad Hasan, Adel O. Sharif (2019)Experimental investigation of the thermal performance of a helical coil latent heat thermal energy storage for solar energy applications, In: Thermal Science and Engineering Progress10pp. 287-298 Elsevier

Thermal performance of a Latent Heat helical coil Thermal Energy Storage (LHTS) was investigated experimentally for both phases; melting and solidification processes. Paraffin wax (type P56-58) and tap water were used as a Phase Change Material (PCM), and a Heat Transfer Fluid (HTF), respectively. The paraffin wax (PCM) thermos-physical properties were determined experimentally. To simulate the solar energy conditions, three different initial temperatures (70 °C, 75 °C and 80 °C) and flow rates (1 L/min, 3 L/min and 5 L/min) of the HTF were tested throughout the PCM melting experiments, while the temperature of HTF was only 30 °C with the same flow rates for solidification process. The storage was completely insulated to reduce the heat losses. The PCM temperature during the melting and solidification processes was measured with time using 16 K-type calibrated thermocouples distributed along the PCM axially and radially. The experimental results showed that contrary to the solidification process, the melting was a superior in the helical coil LHTS under different operational conditions. Axial and radial melting fronts were noticed during the PCM melting process which considerably shortened the melting time under the effect of convection and a shape like a pyramid is formed at the core of the storage. Initial temperature of heat transfer fluid (HTF) was significantly affected the melting process and the increased of it from 70 °C to 75 °C and from 75 °C to 80 °C resulted in shortening the total melting time by about 34.5% and 27.2% respectively. An optimum HTF flow rate was observed during the melting process and it was found to be 3 L/min under the operational conditions of the present experiments. Contrary, the flow rate of HTF was insignificant during the solidification process. The initial temperature of HTF was slightly affected the effectiveness of the melting process. In spite of the efficiency of the melting process, enhancement of the solidification in the coiled LHTS is necessary in order to use the process in the thermal applications of solar energy.

JS Eow, M Ghadiri, AO Sharif, TJ Williams (2001)Electrostatic enhancement of coalescence of water droplets in oil: a review of the current understanding, In: CHEMICAL ENGINEERING JOURNAL84(3)pp. 173-192 ELSEVIER SCIENCE SA
WR Bowen, NJ Hall, LC Pan, AO Sharif, PM Williams (1998)The relevance of particle size and zeta-potential in protein processing, In: NATURE BIOTECHNOLOGY16(8)pp. 785-787 NATURE AMERICA INC
HB Mahood, AN Campbell, Rex Thorpe, AO Sharif (2015)Heat Transfer Efficiency and Capital Cost Evaluation of a Three-Phase Direct Contact Heat Exchanger for the Utilisation of Low-Grade Energy Sources, In: Energy Conversion and Management106pp. 101-109 Elsevier

Low-grade energy cycles for power generation require efficient heat transfer equipment. Using a three-phase direct contact heat exchanger instead of a surface type exchanger, such as a shell and tube heat exchanger, potentially makes the process more efficient and economic. This is because of its ability to work with a very low temperature driving force, as well as its low cost of construction. In this study, an experimental investigation of the heat transfer efficiency, and hence cost, of a three-phase direct contact condenser has been carried out utilising a short Perspex tube of 70 cm total height and 4 cm internal diameter. Only 48 cm was used for the direct contact condensation. Pentane vapour with three different initial temperatures (40℃, 43.5℃ and 47.5℃) was contacted with water with an inlet temperature of 19℃. In line with previous studies, the ratio of the fluid flow rates was shown to have a controlling effect on the exchanger. Specifically, the heat transfer efficiency increased virtually linearly with this ratio, with higher efficiencies also being observed with higher flow 2 rates of the continuous phase. The effect of the initial temperature of the dispersed phase was shown to have a lower order impact than flow rate ratio. The capital cost of the direct contact condenser was estimated and it was found to be less than the corresponding surface condenser (shell and tube condenser) by 30 times. An optimum value of the continuous phase flow rate was observed at which the cost of the condenser is at a minimum. Keywords: Three-phase direct contact condenser, heat transfer efficiency, costing

WR Bowen, AN Filippov, AO Sharif, VM Starov (1999)A model of the interaction between a charged particle and a pore in a charged membrane surface, In: ADVANCES IN COLLOID AND INTERFACE SCIENCE81(1)pp. 35-72 ELSEVIER SCIENCE BV
J Moghadasi, V Dehdari, AO Sharif (2007)Radiotracer applications in reservoir evaluation, In: SPE RESERVOIR EVALUATION & ENGINEERING10(4)pp. 376-381
HB Mahood, AN Campbell, Rex Thorpe, AO Sharif (2015)A new model for the drag coefficient of a swarm of condensing vapour-liquid bubbles in a third immiscible liquid phase, In: CHEMICAL ENGINEERING SCIENCE131pp. 76-83 PERGAMON-ELSEVIER SCIENCE LTD

A semi-analytical model for the drag coefficient of a swarm of two-phase bubbles, condensing in direct contact with an immiscible sub-cooled liquid, has been developed. The analysis used a cellular model configuration, assuming potential (but not inviscid) flow around the reference two-phase bubble in the cell. The effect of the condensation ratio within the two-phase bubbles was included using an approximate relation. The drag coefficient for a wide range of Reynolds numbers (0.1. ≤. Re. ≤. 1000) has been found using the viscous dissipation integral method, and the effect of the liquid content within the two-phase bubble or the half opening angle (β), and the system void fraction (α) were examined. The drag coefficient has been found to increase with the condensation ratio and with the void fraction of the system. The present model agrees well with previously available experimental data and theoretical predictions for single bubbles or particles.

AO Sharif, AA Merdaw, H Al-Bahadili, A Al-Taee, S Al-Aibi, Z Rahal, GAW Derwish (2009)A new theoretical approach to estimate the specific energy consumption of reverse osmosis and other pressure-driven liquid-phase membrane processes, In: Desalination and Water Treatment3(1-3)pp. 111-119
AA Merdaw, AO Sharif, GAW Derwish (2010)Water permeability in polymeric membranes, Part I, In: Desalination260pp. 180-192
HB Mahood, AN Campbell, Rex Thorpe, AO Sharif (2015)Experimental measurements and theoretical prediction for the volumetric heat transfer coefficient of a three-phase direct contact condenser, In: International Communications in Heat and Mass Transfer66pp. 180-188
MK Mohammed, A Yang, A Sharif (2012)Model-based assessment of algal ponds for biomass production under temperate climates, In: 11TH INTERNATIONAL SYMPOSIUM ON PROCESS SYSTEMS ENGINEERING, PTS A AND B31pp. 870-874 ELSEVIER SCIENCE BV
J Moghadasi, V Dehdari, AO Sharif (2006)Radiotracer applications in reservoir evaluation, In: Proceedings - SPE International Symposium on Formation Damage Control2006pp. 379-386

When primary oil production decreases in a field because of reduction in original pressure, water is usually injected to increase oil production. Injected water in special wells (injection wells) forces the oil remaining in certain layers to emerge from other wells (production wells) surrounding the injector. This technique, commonly called secondary recovery, contributes in extracting up to 50% of the original oil in place. Although this technique was first used in old reservoirs where oil production had decreased, it is today a common practice to begin the exploitation of new wells with fluid injection as a way to optimize oil recovery. For this reason, the name secondary recovery is being replaced by the more general term water flooding. Efficiency of the water flooding process is highly dependent on the rock and fluid characteristics. In general, it will be less efficient if heterogeneity is present in the reservoir, such as permeability barriers or high permeability channels that impede a good oil displacement by the injected water [1]. On the other hand Most of the scales found in oil fields forms either by direct precipitation from the water that occurs naturally in reservoir rocks, or as a result of produced water becoming oversaturated with scale components when two incompatible waters meet downhole. The present study attempts to establish the tracer technology as a reliable source of information in scaling experiments and reservoir evaluation such as reservoir heterogeneity. In a series of calcite scaling experiments in sand, Ca2+ was used as a tracer to monitor the CaCO3 precipitation. The results show that the introduction of tracer technology, for the first time in scaling experiments in porous media, has been successful [3]. Copyright 2006, Society of Petroleum Engineers.

An experimental investigation of heat exchange in a three-phase direct contact condenser was carried out using a 70-cm-high Perspex tube with a 4-cm inner diameter. The active direct contact condenser comprised 48 cm. Pentane vapour at three initial temperatures (40℃,43.5℃, and 47.5℃) and water at a constant temperature (19℃) were used as the dispersed and continuous phases, respectively, with different mass flow rate ratios. The results showed that the continuous phase outlet temperature increased with increasing mass flow rate ratio. On the contrary, the continuous phase temperature decreased with increases in the continuous mass flow rate. The initial temperature of the dispersed phase slightly affected the direct contact condenser output, which confirms a latent phase effect in this type of heat exchanger.

The current study highlights the advancement in Pressure Retarded Osmosis (PRO) process and covers most recent development in the process applications. The first application of PRO process goes back to 1973 by Sidney Loeb who suggested using the concept of osmotic energy for power generation. In principle, two solutions of different concentrations are separated by semipermeable membrane of, relatively, high water permeability and solute rejection rate. The high-concentration solution is usually known as the draw solution while the low-concentration solution is called the feed solution. The draw solution is pressurized before entering the membrane. Due to the osmotic pressure gradient across the membrane, fresh water transports in the direction of the osmotic pressure gradients resulting in the dilution of the high-concentration solution. After leaving the membrane, the diluted draw solution is depressurized in a turbine system for power generation. Different types of membrane materials and solute gradient resources were proposed and their impact on the performance of PRO process was investigated. In addition to power generation, the hybridization of PRO process with membrane and thermal processes for power generation and seawater desalination is not unusual nowadays. The current study provides a critical review about the recent advancements in the PRO process and research outcomes.

WR Bowen, AO Sharif (2002)Prediction of optimum membrane design: pore entrance shape and surface potential, In: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS201(1-3)PII S0927-pp. 207-217 ELSEVIER SCIENCE BV
HB Mahood, AO Sharif, S Al-Aibi, D Hawkins, Rex Thorpe (2014)Analytical solution and experimental measurements for temperature distribution prediction of three-phase direct-contact condenser, In: ENERGY67pp. 538-547 PERGAMON-ELSEVIER SCIENCE LTD
AA Merdaw, AO Sharif, GAW Derwish (2011)Mass transfer in pressure-driven membrane separation processes, Part I, In: Chemical Engineering Journal
RW Bowen, AO Sharif (1997)Adaptive finite-element solution of the nonlinear Poisson-Boltzmann equation: A charged spherical particle at various distances from a charged cylindrical pore in a charged planar surface, In: JOURNAL OF COLLOID AND INTERFACE SCIENCE187(2)pp. 363-374 ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS
AA Merdaw, AO Sharif, GAW Derwish (2011)Mass transfer in pressure-driven membrane separation processes, Part II, In: Chemical Engineering Journal
AO Sharif, Z Tabatabaian, WR Bowen (2002)The wall and multivalent counterion effects on the electrostatic force between like-charged spherical particles confined in a charged pore, In: JOURNAL OF COLLOID AND INTERFACE SCIENCE255(1)pp. 138-144 ACADEMIC PRESS INC ELSEVIER SCIENCE
JS Eow, M Ghadiri, AO Sharif (2002)Electrostatic and hydrodynamic flowing separation of aqueous drops in a viscous oil, In: CHEMICAL ENGINEERING AND PROCESSING41(8)PII S0255-pp. 649-657 ELSEVIER SCIENCE SA
M Aryafar, SA Hosseini, AO Sharif (2012)Hybrid desalination method: Application of forward osmosis in desalination, In: EUROMEMBRANE CONFERENCE 201244pp. 1172-1172 ELSEVIER SCIENCE BV
WR Bowen, LC Pan, AO Sharif (1998)Predicting equilibrium constants for ion exchange of proteins - a colloid science approach, In: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS143(1)pp. 117-131 ELSEVIER SCIENCE BV
S Al-aibi, HB Mahood, HB Mahood, AO Sharif, AO Sharif, E Alpay, H Simcoe-Read (2015)Evaluation of draw solution effectiveness in a forward osmosis process, In: Desalination and Water Treatment

© 2015 Balaban Desalination Publications. All rights reserved. This work investigates the effectiveness of sodium chloride and sucrose binary draw solutions in a forward osmosis pilot plant unit with either deionised or salt water feeds. Specifically, the effects of draw solution concentration on water flux through the membrane, the overall water recovery and the specific energy consumption of the unit are considered. For both feed types, sodium chloride draw solution exhibited a relatively high effectiveness in terms of all the measured performance indicators. Further, improvements in flux and recovery were also achievable with an increase in the sodium chloride (draw solution) concentration. In contrast, a sucrose-based draw solution led to a severe deterioration of the membrane performance that could not be effectively overcome by an increase in the draw solution concentration. This observation was attributed to the relatively large increase in the viscosity of the draw solution with increase in sucrose concentration. Interestingly, in the case of a salt water feed, an increase in the sucrose draw solution concentration led to a relatively small increase in flux and recovery, suggesting some complex but favourable interaction between the salt and sucrose due to the reverse diffusion of the salt into the draw solution.

WR Bowen, AO Sharif (1998)Long-range electrostatic attraction between like-charge spheres in a charged pore, In: NATURE393(6686)pp. 663-665 MACMILLAN MAGAZINES LTD
HB Mahood, Rex Thorpe, AN Campbell, AO Sharif (2015)Effect of Various Parameters on the Temperature Measurements In a Three-Phase Direct Contact Condenser, In: International Journal of Thermal Technologies5(1)pp. 23-27
WR Bowen, AO Sharif (1998)Hydrodynamic and colloidal interactions effects on the rejection of a particle larger than a pore in microfiltration and ultrafiltration membranes, In: CHEMICAL ENGINEERING SCIENCE53(5)pp. 879-890 PERGAMON-ELSEVIER SCIENCE LTD
Hameed B. Mahood, Alasdair Campbell, Ali Sh. Baqir, Adel Sharif, Rex Thorpe (2017)Convective Heat Transfer Measurements in a Vapour-Liquid-Liquid Three-Phase Direct Contact Heat Exchanger, In: Heat and Mass Transfer54(6)pp. 1697-1705 Springer Verlag

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40℃,43.5℃ and 47.5℃) was directly contacted with water (the continuous phase) at 19℃. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

WR Bowen, AO Sharif (1999)Long-range electrostatic attraction between like-charge spheres in a charged pore (vol 393, pg 663, 1998), In: NATURE402(6763)pp. 841-841 MACMILLAN MAGAZINES LTD