Preliminary study on supercritical hydrogen and bleed air heat exchanger for aircraft application

2017 ◽  
Vol 232 (12) ◽  
pp. 2231-2243
Author(s):  
Piotr Łapka ◽  
Mirosław Seredyński ◽  
Andrzej Ćwik
Keyword(s):  
Heat Exchanger ◽  
Numerical Models ◽  
Geometrical Parameters ◽  
Commercial Aircraft ◽  
Pressure Drops ◽  
Nusselt Numbers ◽  
Operation Conditions ◽  
Using Data ◽  
Semi Empirical ◽  
Aircraft Application

In this paper, the new idea of the supercritical hydrogen–bleed air heat exchanger for future aircraft propulsion technology is investigated. The proposed heat exchanger will be located in the nacelle of commercial aircraft, and therefore is subjected to several geometrical constrains. At first, the initial geometry was proposed and then based on constrains and assumed operation conditions the main geometrical parameters and dimensions of the heat exchanger were calculated and optimized. The analyses were carried out by developing simple thermo-fluid 1D mathematical and numerical models of the heat exchanger, which were based on its geometrical features, directions of streams of hydrogen, and bleed air as well as on semi-empirical correlations for local Nusselt numbers and pressure drops for supercritical hydrogen and bleed air flows. The 1D model was partially validated using data from the experimental measurements. Then based on the obtained results, the final geometry of the supercritical hydrogen–bleed air heat exchanger was proposed.

Mathematical Modeling and Multi-Objective Optimization of a Mini-Channel Heat Exchanger Via Genetic Algorithm

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Tommaso Selleri ◽  
Behzad Najafi ◽  
Fabio Rinaldi ◽  
Guido Colombo
Keyword(s):  
Genetic Algorithm ◽  
Heat Exchanger ◽  
Multiobjective Optimization ◽  
Pareto Front ◽  
Optimization Procedure ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Objective Functions ◽  
Pressure Drops ◽  
Overall Heat Transfer Coefficient

In the present paper a mathematical model for a mini-channel heat exchanger is proposed. Multiobjective optimization using genetic algorithm is performed in the next step in order to obtain a set of geometrical design parameters, leading to minimum pressure drops and maximum overall heat transfer coefficient. Multiobjective optimization procedure provides a set of optimal solutions, called Pareto front, each of which is a trade-off between the objective functions and can be freely selected by the user according to the specifications of the project. A sensitivity analysis is also carried out to study the effects of different geometrical parameters on the considered functions. The whole system has been modeled based on advanced experimental correlations in matlab environment using a modular approach.

Thermal Analysis and Pressure Loss Modeling for an Optimized Heat Exchanger Used in a Recuperated CO2 Power Cycle

2018 ◽  
Author(s):  
Husam Zawati ◽  
Michael Elmore ◽  
Jayanta Kapat ◽  
Narasimha Nagaiah
Keyword(s):  
Thermal Analysis ◽  
Heat Exchanger ◽  
Initial Pressure ◽  
Specific Power ◽  
Inlet Temperature ◽  
Geometrical Parameters ◽  
Area Density ◽  
Pressure Drops ◽  
Power Cycle ◽  
Net Power Output

A simple recuperated cycle is studied and optimized in this paper. Geometrical parameters for a novel recuperator design are then optimized to minimize area density. The recuperator is where the s-CO2 is analyzed and simulated for both hot and cold sides. The design of the cycle is obtained through a study of a 100 MW net power output s-CO2 cycle, where this cycle features a turbine inlet temperature of 1023 K. The main objective of this paper is to couple a recuperated cycle with a heat exchanger. This is done through Pareto optimality to study the tradeoffs between conflicting variables. The geometry of the heat exchanger features two inlet headers attached to semirectangular channels. The thermal analysis used is based on one-dimensional finite enthalpy method, where discretization is made by equal heat transferred per element. In addition, pressure drops are calculated at both sides of main heat exchanger body. Optimized cycle based on practical parametric assumptions reveals an efficiency of 45.8% and specific power of 132.1 kJ/kg. Best design reveals channel side length of 7 mm with surrounding solid sidewall thickness of 1 mm. Pressure drops for the proposed design are 4.8% and 0.6% of the initial pressure for the hot and the cold sides, respectively. Overall length of the heat exchanger is found to be 10.7 m with an effectiveness of 96.2% and an area density of 363 m2/m3.

The Parametric Study of an Innovative Offset Strip-Fin Heat Exchanger

2007 ◽  
Vol 129 (10) ◽  
pp. 1453-1458 ◽  
Author(s):  
Clayton Ray De Losier ◽  
Sundaresan Subramanian ◽  
Valery Ponyavin ◽  
Yitung Chen ◽  
Anthony E. Hechanova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Coefficient Of Performance ◽  
Channel Height ◽  
Geometrical Parameters ◽  
Pressure Drops ◽  
Trailing Edges ◽  
Parametric Effects ◽  
Temperature Offset ◽  
Offset Strip Fin

Offset strip-fin heat exchangers have numerous applications throughout various industries because they can provide a large amount of heat transfer area in a small volume. The widespread use of the offset strip-fin design has ensured that there are numerous dimensional variations and shown that changes in dimensional parameters affect performance. It is then important to understand how the geometry of an offset strip-fin heat exchanger can affect its performance. Therefore, an investigation into the parametric effects on the global performance of an innovative high-temperature offset strip-fin heat exchanger was numerically performed in this study, where the numerical solution was obtained through a finite-volume method. Computations were carried out for each of the heat exchanger’s geometrical parameters: fin thickness (t), fin length (l), channel height (H), spanwise pitch (px), and the newly introduced gap parameter (g). Also, the effects of rounding the fins leading and trailing edges were investigated, while the heat exchanger’s volume, mass flow rates, and inlet temperatures were kept constant. The results are presented in the form of pressure drops and heat transfer rates, and the coefficient of performance parameter shows that fins with rounded leading and trailing edges outperform fins with rectangular edges.

scholarly journals Predicting the effect of the rib pitch on thermal performance factor of small channels plate heat exchangers fitted with Y and C shapes obstacles

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Sirine Chtourou ◽  
Hassene Djemel ◽  
Mohamed Kaffel ◽  
Mounir Baccar
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Computer Aided Design ◽  
Flow Characteristics ◽  
Plate Heat Exchanger ◽  
Geometrical Parameters ◽  
Computational Domain ◽  
Ansys Fluent ◽  
Plate Heat ◽  
Small Channels

AbstractThis study presents a numerical analysis of a laminar counter flow inside small channels plate heat exchanger fitted with Y and C shape obstacles. Using the Computational Fluid Dynamics CFD, an advanced and modern simulation technique, the influence of the geometrical parameters (such as geometry, rib pitch) on the flow characteristics, the thermal and the hydrodynamics performance of the PHE (plate heat exchanger) is investigated numerically. The main goal of this work is to increase the flow turbulence, enhance the heat transfer and the thermal efficiency by inserting new obstacles forms. The computational domain is a conjugate model which is developed by the Computer Aided Design CAD software Solidworks. The results, obtained with Ansys Fluent, show that the presence of the shaped ribs provides enhancement in heat transfer and fluid turbulence. The CFD analysis is validated with the previous study. The non-dimensional factors such as the Nusselt number Nu, the skin friction factor Cf and the thermo-hydraulic performance parameter THPP are predicted with a Reynolds number Re range of 200–800. The temperature and the velocity distribution are presented and analyzed. The Y ribs and the C ribs offer as maximum THPP values respectively about 1.44 and 2.6 times of a smooth duct.

A New Methodology for the Reliability Based Particle Swarm Optimization with Simulated Annealing

2011 ◽  
Vol 274 ◽  
pp. 101-111 ◽  
Author(s):  
Norelislam Elhami ◽  
Rachid Ellaia ◽  
Mhamed Itmi
Keyword(s):  
Particle Swarm Optimization ◽  
Simulated Annealing ◽  
Numerical Models ◽  
Limit State ◽  
Particle Swarm ◽  
Geometrical Parameters ◽  
Rectangular Plates ◽  
Swarm Optimization ◽  
Reliability Methods ◽  
State Functions

This paper presents a new methodology for the Reliability Based Particle Swarm Optimization with Simulated Annealing. The reliability analysis procedure couple traditional and modified first and second order reliability methods, in rectangular plates modelled by an Assumed Modes approach. Both reliability methods are applicable to the implicit limit state functions through numerical models, like those based on the Assumed Mode Method. For traditional reliability approaches, the algorithms FORM and SORM use a Newton-Raphson procedure for estimate design point. In modified approaches, the algorithms are based on heuristic optimization methods such as Particle Swarm Optimization and Simulated Annealing Optimization. Numerical applications in static, dynamic and stability problems are used to illustrate the applicability and effectiveness of proposed methodology. These examples consist in a rectangular plates subjected to in-plane external loads, material and geometrical parameters which are considered as random variables. The results show that the predicted reliability levels are accurate to evaluate simultaneously various implicit limit state functions with respect to static, dynamic and stability criterions.

Shellside Waterflow Pressure Drop Distribution Measurements in an Industrial-Sized Test Heat Exchanger

1988 ◽  
Vol 110 (1) ◽  
pp. 60-67 ◽  
Author(s):  
H. Halle ◽  
J. M. Chenoweth ◽  
M. W. Wambsganss
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Operating Cost ◽  
Power Requirement ◽  
Pressure Drops ◽  
Pressure Losses ◽  
Finned Tubes ◽  
Heat Exchanger Design ◽  
Isothermal Water

Throughout the life of a heat exchanger, a significant part of the operating cost arises from pumping the heat transfer fluids through and past the tubes. The pumping power requirement is continuous and depends directly upon the magnitude of the pressure losses. Thus, in order to select an optimum heat exchanger design, it is is as important to be able to predict pressure drop accurately as it is to predict heat transfer. This paper presents experimental measurements of the shellside pressure drop for 24 different segmentally baffled bundle configurations in a 0.6-m (24-in.) diameter by 3.7-m (12-ft) long shell with single inlet and outlet nozzles. Both plain and finned tubes, nominally 19-mm (0.75-in.) outside diameter, were arranged on equilateral triangular, square, rotated triangular, and rotated square tube layouts with a tube pitch-to-diameter ratio of 1.25. Isothermal water tests for a range of Reynolds numbers from 7000 to 100,000 were run to measure overall as well as incremental pressure drops across sections of the exchanger. The experimental results are given and correlated with a pressure drop versus flowrate relationship.

scholarly journals Execution of a Smart Prediction Tool to Evaluate Thermal Performance in a heat exchanger by using Single Elliptical Leaf Strips with altered Angle

2019 ◽  
Vol 8 (11) ◽  
pp. 123-131
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
Industrial Applications ◽  
Generalized Regression Neural Network ◽  
Prediction Tool ◽  
Pressure Drops ◽  
Transfer Rates ◽  
Mass Flow Rates

Heat exchangers are prominent industrial applications where engineering science of heat transfer and Mass transfer occurs. It is a contrivance where transfer of energy occurs to get output in the form of energy transfer. This paper aims at finding a solution to improve the thermal performance in a heat exchanger by using passive method techniques. This experimental and numerical analysis deals with finding the temperature outlets of cold and hot fluid for different mass flow rates and also pressure drop in the tube and the annular side by adding an elliptical leaf strip in the pipe at various angles. The single elliptical leaf used in experiment has major to minor axes ratios as 2:1 and distance of 50 mm between two leaves are arranged at different angular orientations from 0 0 to 1800 with 100 intervals. Since it’s not possible to find the heat transfer rates and pressure drops at every orientation of elliptical leaf so a generalized regression neural network (GRNN) prediction tool is used to get outputs with given inputs to avoid experimentation. GRNN is a statistical method of determining the relationship between dependent and independent variables. The values obtained from experimentation and GRNN nearly had precise values to each other. This analysis is a small step in regard with encomiastic approach for enhancement in performance of heat exchangers

scholarly journals COMBINING DATA-DRIVEN AND NUMERICAL MODELLING APPROACHES TO STORM EROSION PREDICTION

2020 ◽  
pp. 38
Author(s):  
Joshua Simmons ◽  
Kristen Splinter
Keyword(s):  
Numerical Models ◽  
Individual Performance ◽  
Study Data ◽  
Data Driven ◽  
Erosion Prediction ◽  
Trade Offs ◽  
Combining Data ◽  
Erosion Models ◽  
Using Data ◽  
The Individual

Physics-based numerical models play an important role in the estimation of storm erosion, particularly at beaches for which there is little historical data. However, the increasing availability of pre-and post-storm data for multiple events and at a number of beaches around the world has opened the possibility of using data-driven approaches for erosion prediction. Both physics-based and purely data-driven approaches have inherent strengths and weaknesses in their ability to predict storm-induced erosion. It is vital that coastal managers and modelers are aware of these trade-offs as well as methods to maximise the value from each modelling approach in an increasingly data-rich environment. In this study, data from approximately 40 years of coastal monitoring at Narrabeen-Collaroy Beach (SE Australia)has been used to evaluate the individual performance of the numerical erosion models SBEACH and XBeach, and a data-driven modelling technique. The models are then combined using a simple weighting technique to provide a hybrid estimate of erosion.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/v53dZiO8Y60

scholarly journals Parameterization of ion-induced nucleation rates based on ambient observations

2010 ◽  
Vol 10 (9) ◽  
pp. 21697-21720 ◽  
Author(s):  
T. Nieminen ◽  
P. Paasonen ◽  
H. E. Manninen ◽  
V.-M. Kerminen ◽  
M. Kulmala
Keyword(s):  
Large Scale ◽  
Formation Rate ◽  
Global Radiation ◽  
Atmospheric Models ◽  
Organic Vapor ◽  
Depth Analysis ◽  
Using Data ◽  
One Year ◽  
Project Data ◽  
Semi Empirical

Abstract. Atmospheric ions participate in the formation of new atmospheric aerosol particles, yet their exact role in this process has remained unclear. Here we derive a new simple parameterization for ion-induced nucleation or, more precisely, for the formation rate of charged 2-nm particles. The parameterization is semi-empirical in the sense that it is based on comprehensive results of one-year-long atmospheric cluster and particle measurements in the size range ∼1–42 nm within the EUCAARI (European Integrated project on Aerosol Cloud Climate and Air Quality interactions) project. Data from 12 field sites across Europe measured with different types of air ion and cluster mobility spectrometers were used in our analysis, with more in-depth analysis made using data from four stations with concomitant sulphuric acid measurements. The parameterization was given in two slightly different forms: a more accurate one that requires information on sulfuric acid and nucleating organic vapor concentrations, and a simpler one in which this information is replaced with the global radiation intensity. In principle, these new parameterizations are applicable to all large-scale atmospheric models containing size-resolved aerosol microphysics.

scholarly journals Turbulent vertical diffusivity in the sub-tropical stratosphere

2007 ◽  
Vol 7 (3) ◽  
pp. 6603-6629 ◽  
Author(s):  
I. Pisso ◽  
B. Legras
Keyword(s):  
Transport Model ◽  
Numerical Models ◽  
Small Scale ◽  
Chemistry Transport Model ◽  
Weather Forecasts ◽  
Chemical Tracers ◽  
Vertical Diffusivity ◽  
Large Ensembles ◽  
Local Equivalent ◽  
Using Data

Abstract. Vertical (cross-isentropic) mixing is produced by small-scale turbulent processes which are still poorly understood and parametrized in numerical models. In this work we provide estimates of local equivalent diffusion in the lower stratosphere by comparing balloon borne high-resolution measurements of chemical tracers with reconstructed mixing ratio from large ensembles of random Lagrangian backward trajectories using European Center for Medium-range Weather Forecasts analysed winds and a chemistry-transport model (REPROBUS). We have investigated cases in subtropical latitudes using data from HIBISCUS campaign. Upper bound on the vertical diffusivity is found to be of the order of 0.5 m2 s−1 in the subtropical region, which is larger than the estimates at higher latitudes. The relation between diffusion and dispersion is studied by estimating Lyapunov exponents and studying their variation according to the presence of active dynamical structures.

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