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Papers by Derek Ingham

Journal of The Energy Institute, Aug 1, 2023

Applications of Nature-Inspired Computing in Renewable Energy Systems, 2022

A new integrated hybrid solar thermal and wind-based microgrid power system is proposed. It consi... more A new integrated hybrid solar thermal and wind-based microgrid power system is proposed. It consists of a concentrated parabolic solar dish Stirling engine, a wind turbine, and a battery bank. The electrical power curtailment is diminished, and the levelised cost of energy is significantly reduced. To achieve these goals, the present study conducts a dynamic performance analysis over one year of operation. Further, a multi-objective optimisation model based on a genetic algorithm is implemented to optimise the techno-economic performance. The MATLAB/Simulink® software was used to model the system, study the performance under various operating conditions, and optimise the proposed hybrid system. Finally, the model has been implemented for a specific case study in Mafraq, Jordan. The system satisfies a net power output of 1500 kWe. The developed model has been validated using published results. In conclusion, the obtained results reveal that the optimised model of the microgrid can su...

International Journal of Heat and Mass Transfer, 2018

Abstract The flow behaviour of a falling film on horizontal tubes has significant impacts on the ... more Abstract The flow behaviour of a falling film on horizontal tubes has significant impacts on the efficiency of heat and mass transfer for the horizontal tubular evaporators and absorbers. Thus it is crucial to investigate the effect of contact angle and specific flow rate on the hydrodynamics of films and droplets in the drop and jet modes, which are the most important modes for evaporators and absorbers. A three-dimensional CFD model, using the volume of fluid (VOF) method, has been built to capture the gas-liquid interface. By employing mesh refinement and independence tests, the film spreading and droplet formation, liquid bridge breakup, droplet detachment, impact and fluctuation waviness of the simulations at the completely wetting condition are found to be in good agreement with experimental data and theory. In the drop mode, the behaviours of the droplets alternately falling from neighboring sites, including unstable slender liquid bridge and complex saddle waves were observed. This indicates that the wave propagation speed at first is higher than the impaction speed. In the in-line jet mode, the flow pattern is almost stationary but it is perturbed weakly by the impaction wave. The circumferential ring film has its maximum thickness located at the middle of the two-column in-line jet due to the wave interaction. In addition, the wetting area, spreading speed and instability time of the falling film are reduced with an increase in the contact angle, while the first two parameters increase at higher specific flow rates. In particular, an overshoot occurred at the larger contact angle. Finally, the results showed that the falling film flow pattern is sensitive to the initial wetting condition. Further, it reveals that the final steady wetted region depends on the receding contact angle, thus the introduction of the dynamic contact angle is the best approach for accurately determining the behaviour of falling films.

The paper presents an implementation of a user interface for the capture and refinement of CFD da... more The paper presents an implementation of a user interface for the capture and refinement of CFD data for building energy analysis (CaRCA) that allows interaction with building data in a context and language familiar to the CFD engineer. This is made possible by the use of an International Standards Organisation - standard for the exchange of product model data (ISO-STEP) compliant building product model (BPM). The BPM used is the International Alliance for Interoperability (IAI) developed industry foundation classes (IFC) schema. This allows early introduction of the CFD engineer to the building lifecycle and a method for recorded validation of CFD predictions.

Volume 3: Combustion, Fuels and Emissions, Parts A and B, 2008

ABSTRACT Numerical solutions of a turbulent jet flow are used to provide velocity information thr... more ABSTRACT Numerical solutions of a turbulent jet flow are used to provide velocity information throughout a simple cold turbulent propane jet at a Reynolds number of 68,000. Predictions provided by the Reynolds-averaged Navier-Stokes simulations, based on a Reynolds stress turbulence model, are compared with experimental data available in the literature. The effect of the modelled inlet boundary conditions on the predicted flow field is described, and the discrepancy between the simulation results and experiment measurements is found to be less than the corresponding variations due to uncertainness in the experimental boundary conditions. In addition, these solutions are used as the basis for noise predictions for the jet based on Lighthill’s theory using the Goldstein broadband noise source formalization that postulates axisymmetric turbulence superposed on the mean flow. The latter model provides an aeroacoustic tool that is reasonable in identifying components or surfaces that generate significant amounts of noise, thereby providing opportunities for early design changes to aircraft and gas turbine components.

Volume 4: Turbo Expo 2007, Parts A and B, 2007

ABSTRACT This paper presents computational predictions of adiabatic film cooling effectiveness fo... more ABSTRACT This paper presents computational predictions of adiabatic film cooling effectiveness for effusion cooling systems with 90° and 30° holes. Predictions are performed for a range of coolant injection mass flow rates per unit surface area, G, of 0.1kg/sm2 - 1.6 kg/sm2 for 90° holes with constant pitch-to-diameter ratio of X/D = 11 and 10 rows of holes and for 30° inclined holes with X/D = 11 and 15 rows of holes over a 152mm surface length. The computational works performed are steady-state and the turbulent governing equations are solved by a control-volume-based finite difference method with second-order upwind scheme and the k-epsilon turbulence model. The velocity and pressure terms of momentum equations are solved by the SIMPLE method. The CFD prediction were validated by comparing the predictions with literature data for single rows of inclined holes and then applied to effusion cooling. The predictions included the use of a tracer gas in the coolant, which was used to predict the mixing of the coolant with the hot mainstream gases. Also the surface distribution of the tracer gas was a direct prediction of the cooling effectiveness. The mixing of coolant with the mainstream was studied and boundary layer temperature and coolant mixing profiles were predicted. These were compared with temperature measurement in a hot effusion cooling test rig.

Journal of Heat Transfer, 1988

Numerical investigations are conducted into steady laminar combined convection flows in vertical ... more Numerical investigations are conducted into steady laminar combined convection flows in vertical parallel plate ducts with asymmetric constant wall temperature boundary conditions. The streamwise diffusion terms in the governing equations are neglected and the resulting parabolic equations are expressed in an implicit finite difference scheme and solved using a marching technique. In certain situations the combination of the size of the ratio |Gr/Re| and the difference in temperature between the walls of the duct is such that the fully developed flow profile, as the streamwise coordinate tends toward infinity, includes reverse flow in the vicinity of the cold wall. Techniques first used in a previous study are employed in finding a solution through the whole domain of the fluid for those situations involving reverse flow in the fully developed region. Comparisons with existing data near the duct entrance and far along the duct show very good agreement.

International Journal of Heat and Mass Transfer, 1996

Analytical and numerical solutions are presented for the problem of steady, natural convection fr... more Analytical and numerical solutions are presented for the problem of steady, natural convection from a sinusoidally heated and cooled horizontal surface which is embedded in a fluid saturated porous media which is maintained at a constant temperature T~. The plate is assumed to have a harmonic temperature variation, and at large distances from the plate we investigate two different boundary conditions, namely, when we enforce either a constant temperature T~ or an adiabatic boundary condition. For small values of the Rayleigh number an analytical solution has been obtained provided that the temperature at infinity is constant but depends on the Rayleigh number or there is zero heat flux at infmity. On specifying an arbitrary temperature T~ at infinity then no analytical solution could be obtained and the numerical solution procedure was not convergent. However, we were able to obtain an analytical solution in the situation when the constant temperature T~o is enforced at a finite distance, say y = d, from the plate and, as d~ ~, the solution approaches that obtained by enforcing the adiabatic condition at infinity. When the constant temperature T~ is enforced at the station y = d we found that the numerical solution is dependent on the value of d, but when the zero heat flux condition is enforced at y = d we obtained th at d = 4n is sufficiently large for the solution to be independent of the value of d. At very small values of Ra there is very good agreement between the analytical and numerical solutions and when Ra is very large the boundary-layer scalings for the Nusselt number and the mean fluid velocity along the plate are confirmed by the numerical calculations.

Aerospace Science and Technology, 2012

Wall cavities have been widely used as flameholders in scramjet engines to prolong the residence ... more Wall cavities have been widely used as flameholders in scramjet engines to prolong the residence time of the fuel and the air in supersonic flow. These devices improve the combustion efficiency of the scramjet combustor, and also impose additional drag on the engine. In this paper, the two-dimensional coupled implicit NS equations, the standard k-ε turbulence model and the finite-rate/eddy-dissipation reaction model have been applied to simulate numerically the combustion flow field of a hydrogen-fueled scramjet combustor with a cavity flameholder. The effects of the geometric parameters, i.e. the upstream depth, the ratio of the length to the upstream depth, the ratio of the downstream to the upstream depth and the swept angle, on the drag force of the cavity flameholder for a heated flow are investigated using the variance analysis method. The obtained results show that the variance analysis method can be used to accurately analyze the effects of the geometric parameters on the performance of the cavity flameholder. The effects of the ratios of the length to the upstream depth and of the downstream to the upstream depth on the drag force of the cavity flameholder are substantial, and they must be foremost when considering the design of the cavity flameholder. At the same time, when the downstream depth is equal to the upstream depth, the drag force of the cavity flameholder is the largest, and on increasing the ratio of the length to the upstream depth, the drag force on the cavity flameholder varies from negative to positive. A cavity flameholder with a large ratio of the length to the upstream depth brings large drag force in the combustion flow field.

Journal of Energy Resources Technology, 2021

The aerodynamic shapes of the blades are still of high importance and various aerodynamic designs... more The aerodynamic shapes of the blades are still of high importance and various aerodynamic designs have been developed in order to increase the amount of energy production. In this study, a swept horizontal axis wind turbine blade has been optimized to increase the aerodynamic efficiency using the computational fluid dynamics method. To illustrate the technique, a wind turbine with a rotor diameter of 0.94 m has been used as the baseline turbine, and the most appropriate swept blade design parameters, namely the sweep start-up section, tip displacement, and mode of the sweep have been investigated to obtain the maximum power coefficient at the design tip speed ratio. At this stage, a new equation that allows all three swept blade design parameters to be changed independently has been used to design swept blades, and the response surface method has been used to find out the optimum swept blade parameters. According to the results obtained, a significant increase of 4.28% in the power ...

Fuel Processing Technology, 2018

The transient nature of a flame can be quantified by performing spectral and oscillatory analysis... more The transient nature of a flame can be quantified by performing spectral and oscillatory analysis of its parameters, such as luminance and temperature. This paper presents an assessment of the effect of an oxyfuel environment on the combustion of two different solid fuels, a high volatile bituminous coal and a white wood biomass, in a 250 kWth pilot-scale combustion test facility. A digital flame monitoring system was fitted to the experimental furnace, and was used to record high speed videos of the flame. Transient signals for both digital luminance and temperature were obtained after the instantaneous frames were extracted from the original videos. Spectral analysis was performed over the transient signal in order to analyse the temporal coherence of the flame through a weighted oscillation frequency value. An additional parameter, the oscillation index, which accounts for the amplitude of the oscillation of the flame, was computed to complement the information recovered from the flame. The oscillation trends obtained from these experiments assess the dynamic response of the flame to different combustion environments within the furnace. In general, it was found that oxyfuel flames showed a discernible temporal repeatability and a lower magnitude of the oscillation of their flame parameters, and therefore are registered as being more stable than their counterpart under air combustion conditions. In addition, the biomass flames exhibit less sensitivity to the oxyfuel combustion environment than what was found with coal, which may allow future oxy-biomass regimes to operate under a much wider envelop of firing conditions.

International Journal of Greenhouse Gas Control, 2019

Selective exhaust gas recirculation (S-EGR) is an option proposed to augment the CO 2 content in ... more Selective exhaust gas recirculation (S-EGR) is an option proposed to augment the CO 2 content in the flue gases of gas-fired systems, facilitating integrated post-combustion CO 2 capture. However, issues such as flame instabilities and increases in unburned species require careful analysis. The performance of a micro-gas turbine under simulated S-EGR conditions is evaluated here. Maximum flue gas CO 2 concentrations of 8.4 and 10.1 vol% were achieved at power outputs of 100 and 60 kW e , respectively; a 4-7 times increase in CO 2 content compared to the baseline cases-similar to what can be achieved with S-EGR systems. Impacts on the operational performance of the system were assessed, together with the resulting CO, unburned hydrocarbon and nitrogen oxide (NOx) emission trends. The electrical efficiency reduced slightly under S-EGR conditions and emissions of unburned and partially oxidised species increased, especially at lower loads, where incomplete combustion effects were more prominent. The rotational speed of the engine decreased under S-EGR conditions as a result of the change in the oxidiser properties, with the compressor discharge temperatures also decreasing slightly. Furthermore, NOx emissions were lower in S-EGR scenarios due to the expected lower flame temperatures, which leads to reduced thermal NOx production.

Inorganic chemistry, Jan 3, 2017

The estimation of the thermochemical radius is very important because most of the properties of t... more The estimation of the thermochemical radius is very important because most of the properties of the electrolyte solutions are, to some extent, linked to this property. Also, these thermochemical radii can be used to estimate lattice energies, which can be a very important parameter to be evaluated when assessing the possibility of synthesizing new inorganic materials. This study presents a formulation for estimating the thermochemical radii of complex ions. More specifically, these thermochemical radii are estimated using a weighted sum based on the radii of the contributing cations and anions. Also, the influence of the ionic charge on these thermochemical radii is assessed and discussed. Finally, the parameters obtained from the estimation of the thermochemical radii of complex cations are used to estimate cation volumes, and this estimation is then validated through comparison with literature values. As a result, the equations developed for thermochemical radii of complex ions pr...

Mathematical Problems in Engineering, 2015

Recently hydraulic fracturing of rocks has received much attention not only for its economic impo... more Recently hydraulic fracturing of rocks has received much attention not only for its economic importance but also for its potential environmental impact. The hydraulically fracturing technique has been widely used in the oil (EOR) and gas (EGR) industries, especially in the USA, to extract more oil/gas through the deep rock formations. Also there have been increasing interests in utilising the hydraulic fracturing technique in geological storage of CO2in recent years. In all cases, the design and implementation of the hydraulic fracturing process play a central role, highlighting the significance of research and development of this technique. However, the uncertainty behind the fracking mechanism has triggered public debates regarding the possible effect of this technique on human health and the environment. This has presented new challenges in the study of the hydraulic fracturing process. This paper describes the hydraulic fracturing mechanism and provides an overview of past and r...

Engineering Analysis with Boundary Elements, 1993

A new implementation of the boundary element method solution technique has been devised to invest... more A new implementation of the boundary element method solution technique has been devised to investigate time-dependent heat transfer. This new approach has been applied to the problem of oscillatory heat transfer in an isolated fin. A comparison of the results with an existing analytical solution indicates that the boundary element technique developed in this paper is very efficient. Results are obtained for an aluminium fin over a wide range of heat transfer coefficients, fin dimensions and amplitude and frequency of the base temperature oscillation of the fin.

Engineering Analysis with Boundary Elements, 1991

The entry flow and the trajectories of small solid particles into a fibrous filter is investigate... more The entry flow and the trajectories of small solid particles into a fibrous filter is investigated. Both viscous (creeping) and potential flows have been considered using the Boundary Element Method in which an upstream asymptotic solution has been used in order to eliminate the effects due to large aspect ratios. Results for the collection efficiency are presented as functions of the Stokes number for both types of flows. For potential flow it was found that the single fibre collection efficiency of the first row was increased by adding a second row and further increased as the row separation was reduced. The opposite effect was observed for the case of creeping flow.

Journal of Hydraulic Research, 2011

ABSTRACT A Computational Fluid Dynamics (CFD) investigation was conducted to evaluate the accurac... more ABSTRACT A Computational Fluid Dynamics (CFD) investigation was conducted to evaluate the accuracy and validity of the algebraic slip model in predicting the evolution of turbidity currents. The scenario used to run the model simulation was an experimental lock release of mono-disperse and bi-disperse turbidity currents. The general flow structure of the simulated currents compares well with the general experimental observation. The model used predicts the deposition from currents carrying coarse particles relatively well but excessively over-predicts the deposition rate in currents carrying fine particles. Incorporation of the Simonin model turbulence dispersion into the original model reduces the sediment deposition rate but incurs an excessive dispersion force. Thus, still another turbulence modulation model was incorporated into the finally proposed version and the mono-disperse flow was then re-simulated, and yet only small changes were observed in the results. It is concluded that improved results will be achieved by using more accurate turbulence dispersion models.

Journal of Fuel Cell Science and Technology, 2005

This paper presents a review of the current situation in the computational fluid dynamics (CFD) m... more This paper presents a review of the current situation in the computational fluid dynamics (CFD) modeling of fuel cells and highlights the significant challenges that lie ahead in the development of a comprehensive CFD model for fuel cell applications. The paper focuses on the issues concerned with solid oxide fuel cells and proton exchange membrane fuel cells because these are the two most poplar and probably the most promising types of fuel cells for both stationary and transport applications. However, the general principles presented in this paper are applicable to all types of fuel cells.

As one of the most promising propulsive systems in the future, the scramjet engine has drawn the ... more As one of the most promising propulsive systems in the future, the scramjet engine has drawn the attention of many researchers. The two-dimensional coupled implicit NS equations, the standard k-e turbulence model and the finite-rate/eddy-dissipation reaction model have been applied to numerically simulate the flow field of the hydrogen fueled scramjet combustor with a cavity flameholder under two different working conditions, namely, cold flow and engine ignition. The obtained results show that the numerical method used in this paper is suitable to simulate the flow field of the scramjet combustor. The static pressure distribution along the top and bottom walls for the case under the condition of engine ignition is much higher than that for the case under the condition of cold flow. There are three clear pressure rises on the top and bottom walls of the scramjet combustor. The eddy generated in the cavity acts as a flameholder in the combustor, and it can prolong the residence time ...