Multivariate design and analysis of aircraft HEX under multiple working conditions within flight envelope

2021 ◽  
pp. 1-18
Author(s):  
Qihang Liu ◽  
G.Q. Xu ◽  
Jie Wen ◽  
Yanchen Fu ◽  
Laihe Zhuang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Design Method ◽  
Structural Parameters ◽  
Optimal Structure ◽  
Clear Correlation ◽  
Pressure Drops ◽  
Design Variables ◽  
Wide Range ◽  
Common Weight

Abstract This paper presents a multi-condition design method for the aircraft heat exchanger (HEX), marking with light weight, compactness and wide range of working conditions. The quasi-traversal genetic algorithm (QT-GA) method is introduced to obtain the optimal values of five structural parameters including the height, the tube diameter, the tube pitch, and the tube rows. The QT-GA method solves the deficiency of the conventional GA in the convergence, and gives a clear correlation between design variables and outputs. Pressure drops, heat transfer and the weight of the HEX are combined in a single objective function of GA in the HEX design, thus the optimal structure of the HEX suitable for all the working conditions can be directly obtained. After optimization, the weight of the HEX is reduced to 2.250 kg, more than 20% lower than a common weight of around 3 kg. Based on the optimal structure, the off-design performance of the HEX is further analyzed. Results show that the extreme working conditions for the heat transfer and the pressure drops are not consistent. It proves the advance of the multi-condition design method over traditional single-condition design method. In general, the proposed QT-GA design method is an efficient way to solve the multi-condition problems related to the aircraft HEX or other energy systems.

Development of a Computer Program for the Numerical Investigation of Heat Transfer in a Gasketed Plate Heat Exchanger

2010 ◽  
Author(s):  
Gizem Gulben ◽  
Selin Aradag ◽  
Nilay Sezer-Uzol ◽  
Ufuk Atamturk
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Computer Program ◽  
Working Conditions ◽  
Convective Heat Transfer Coefficient ◽  
Plate Heat Exchanger ◽  
Design Parameters ◽  
Outlet Temperature ◽  
Pressure Drops ◽  
Plate Heat

In this study, a computer program is developed to calculate characteristics of a Chevron type gasketed plate heat exchanger (CTGPHEX) such as: the number of plates, the effective surface area and total pressure drops. The main reason to prefer the use of CTGPHEXs to other various types of heat exchangers is that the heat transfer efficiency is much higher in comparison. Working conditions such as the flow rates and inlet and outlet temperature of both flow sides and plate design parameters are used as an input in the program. The Logarithmic Mean Temperature Method and the different correlations for convective heat transfer coefficient and Fanning factor that are found in the literature are applied to calculate the minimum necessary effective heat transfer area, the number of plate and pressure drops due to friction for both fluid sides of fulfill the desired heat transfer rate. This Turkish / English language optioned user friendly computer program is targeted to be used in domestic companies to design and select CTGPHEXs for any desired working conditions.

A Safety Factor Method for Reliability-Based Component Design

2021 ◽  
pp. 1-34
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to several iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so is the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

Experimental Investigation on Swirl and Heat Transfer Within a Rotor-Stator Cavity

2016 ◽  
Author(s):  
Daniele Massini ◽  
Bruno Facchini ◽  
Mirko Micio ◽  
Riccardo Da Soghe
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Mass Flow Rate ◽  
Working Conditions ◽  
Mass Flow ◽  
Flow Rate ◽  
System Effect ◽  
Flow Measurements ◽  
Wide Range ◽  
Admission System

A rotating test rig, reproducing a rotor-stator cavity with an axial admission system, has been exploited for an experimental investigation on the internal flow field and its effect on heat transfer on the stator side. Working conditions were varied in a wide range of rotating velocities and superposed mass flow rates. 2D PIV flow measurements were performed in order to obtain a radial distribution of the tangential velocity, results were used to validate numerical simulations aimed at understanding the admission system effect on the swirl distribution. Heat transfer coefficient distribution along the stator disk has been evaluated performing a steady state technique exploiting Thermo-chromic Liquid Crystals (TLC). Tests have been performed varying the superposed mass flow rate up to reaching the condition of cavity completely sealed, further increase of the mass flow rate showed to reduce the effect of the rotation. Working conditions were set in order to investigate cases missing in open literature, however few tests performed in similarity with other researches provided comparable results.

Optimization of Integrally Stiffened Panels Based on Crack Propagation Life

2008 ◽  
Vol 33-37 ◽  
pp. 249-254
Author(s):  
Zhi Ping Yin ◽  
Qi Qing Huang ◽  
Bing Hui Zhang
Keyword(s):  
Crack Propagation ◽  
Structural Optimization ◽  
Optimization Design ◽  
Design Method ◽  
Structural Parameters ◽  
Stiffened Panels ◽  
Structural Fatigue ◽  
Design Variables ◽  
Optimization Methodology ◽  
Integrally Stiffened Panels

Recent development in structure optimization offers the potential for significant improvements in the design of more durable structures. The present paper reveals the importance of structural optimization with crack propagation life of integrally stiffened panels. In the full paper, we explain in detail how to optimize structural fatigue life and design the structure of integrally stiffened panels which has the optimization life. The first topic is: the review of existing structural optimization design method. The second topic is: optimization methodology with crack propagation life. In our optimization methodology, the RSM (Response Surface Methodology) and GA (Genetic Algorithm) are successfully applied for structural optimization design with crack propagation life. The third topic is: damage tolerance optimization of integrally stiffened panels with crack propagation life. In this paper, structural parameters: the height and location of stringer, are the design variables. The structural weight is a fixed value. Through analyzing, the optimization structure with maximum life can not simply be chosen, and the maximum life would not increase all ways while the high of stringer increased. At last, the optimization structure, which has maximum crack propagation life, is given on the integrally stiffened panels.

A Novel Approach of Designing Aircraft Heat Exchanger for Continuous Working Conditions Using Modified Genetic Algorithm

2019 ◽  
Author(s):  
Qihang Liu ◽  
Laihe Zhuang ◽  
Yanchen Fu ◽  
Bensi Dong ◽  
Jie Wen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Heat Transfer Rate ◽  
Working Conditions ◽  
Transfer Rate ◽  
Optimization Design ◽  
Working Condition ◽  
Structural Parameters ◽  
Novel Approach

Abstract A novel approach is proposed to design an aircraft heat exchanger considering multiple working conditions to develop the conventional approach that designs for only one working condition. Calculation results show that the performance of the heat exchangers designed by this novel approach meets the requirement of pressure drop and heat transfer for all working conditions (flight height varies from 0 m to 12,000 m, and Mach number varies from 0 to 1.2). After working conditions discrete and heat exchanger design, the extreme working conditions of pressure drop and heat transfer rate are found not coincided, which have been all considered in design without artificially screening. Therefore, it is not necessary to find a ‘seeming extreme working condition’ before design for this approach. In the optimization design, a deeply optimized structure of heat exchanger is proposed by changing the values of the selected structural parameters to reduce by roughly 30% of the total weight in comparison to common design results. Moreover, the pressure drop and the heat transfer rate of the optimal result can be reasonably distributed at different working conditions. Actually in this novel approach, more other specific criteria required could be also added into the integrate criterion of optimization to control the result. In addition, two detailed optimization methods, sacrifice of secondary objective parameters and ‘the macro-to-micro design method’, have been proposed in optimization design for further optimal structure.

A Robust Mixing Plane Method and its Application in 3D Inverse Design of Transonic Turbine Stages

2014 ◽  
Author(s):  
Saurya Ranjan Ray ◽  
Mehrdad Zangeneh
Keyword(s):  
Design Method ◽  
Flow Direction ◽  
Flow Analysis ◽  
Inverse Design ◽  
Plane Method ◽  
Design Variables ◽  
Wide Range ◽  
Inverse Design Method ◽  
Flow Variables ◽  
Flux Conservation

A robust mixing plane method satisfying interface flux conservation, non-reflectivity and retaining interface flow variation; valid at all Mach numbers and applicable for any machine configuration is formulated and implemented in a vertex based finite volume solver for flow analysis and inverse design of turbomachinery stage configurations. The formulation is based on superposing perturbed flow variables in the form of 3D characteristics obtained along the flow direction on the exchanged mixed out average quantities at the stage interface. A condition is derived in the mixed-out averaging procedure to distinguish between the subsonic and supersonic flow conditions at the interface. Using preconditioning technique, the new functionality is demonstrated to be applicable for a wide range of interface conditions and over different machine configurations with small spatial gap across the blade rows. The method is shown to satisfy flux conservation across the interface without generating spurious oscillations in the flow field at the domain boundaries and validated against available commercial solvers. Subsequently, a blade re-design approach in a multi-row configuration is conceptualised and demonstrated by the application of the 3D inverse design method on a single stage Low Pressure Turbine. Meridional load variation, stage reaction and blade stacking angle are considered as the design variables to explore the design space. Conducting design runs at a fixed mass flow boundary condition and similar overall loading condition; the optimised configuration is shown to satisfy redistributed meridional load, providing performance improvement while maintaining a similar level of flow rate and work extraction as the baseline configuration.

Condensation heat transfer and pressure drop of R134a inside microfin tubes: Effect of fin height and fin angle

2007 ◽  
Vol 221 (1) ◽  
pp. 43-53 ◽  
Author(s):  
R K Al-Dadah ◽  
A D Naser
Keyword(s):  
Heat Transfer ◽  
Experimental Results ◽  
Condensation Heat Transfer ◽  
Smooth Tube ◽  
Transfer Coefficients ◽  
Pressure Drops ◽  
Mass Fluxes ◽  
Wide Range ◽  
Spiral Angle ◽  
Microfin Tubes

In this paper, the effects of fin height and fin angle on condensation heat transfer inside microfin tubes were investigated. One smooth and six microfin tubes with outer diameters of 9.52 mm were used to condense R134a at 30 °C and a mass flux range 157–347 kg/m2s. Each of the microfin tubes tested had 60 fins and a spiral angle of 18°. In three of these tubes only the fin height was altered to 0.15, 0.20, or 0.25 mm while the fin angle remained at 30°. The remaining microfin tubes had altered fin angles to 40, 50, or 60°, with the fin heights remaining at 0.20 mm. Experimental results showed that microfin tubes had distinct performance advantages over the smooth tube. Particularly, the microfin tube with fin height of 0.20 mm and fin angle of 50° produced condensation heat transfer coefficients 215–250 per cent higher than those of the smooth tube, with average increases in pressure drops at 115–160 per cent. Four frequently cited correlations were used to predict the heat transfer coefficient for condensation inside smooth tubes. Of these correlations, the predictive method proposed by Cavallini et al. [1] that takes into account the wide range of flow patterns encountered in condensation at various mass fluxes was found to best predict the experimental results. For microfin tubes, the model by Yu and Koyama [2] predicted the experimental results with least deviation from experimental results compared to that of Cavallini et al. [3, 4] and that of Kedzierski and Goncalves [5].

Dynamic Analysis and Structural Optimization for a Logging while Drilling Neutron Instrument

2014 ◽  
Vol 684 ◽  
pp. 70-75
Author(s):  
Chao Wei ◽  
Qiu Yue Sun ◽  
Yuan Ying Qiu ◽  
Jun Jie Ye
Keyword(s):  
Design Method ◽  
Structural Parameters ◽  
Dynamic Performance ◽  
Resonance Region ◽  
Base Frequency ◽  
Influence Curves ◽  
Design Variables ◽  
Logging While Drilling ◽  
Vibration Performance ◽  
Pulsed Neutron

Logging while drilling (LWD) neutron instrument is a core equipment of the pulsed neutron logging technology, its anti-vibration performance has a direct impact on the measurement accuracy. For improving the anti-vibration performance, a reverse design method was proposed to avoid the resonance region due to increasing structural stiffness. The dynamic performance of the original instrument was analyzed, the weaknesses of its anti-vibration performance were determined and its topologies were improved. Moreover, the structural parameters of the instrument were optimized to raise the structural base frequency. The results show that the base frequency of the instrument increases high enough, the influence curves and surfaces of the base frequency with design variables provide a theoretical reference for the design of a LWD neutron instrument.

A Practical Safety Factor Method for Reliability-Based Component Design

2020 ◽  
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to a number of iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so it the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

scholarly journals Study of Pressure Drops and Heat Transfer of Nonequilibrial Two-Phase Flows

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2275
Author(s):  
Aleksandr V. Belyaev ◽  
Alexey V. Dedov ◽  
Ilya I. Krapivin ◽  
Aleksander N. Varava ◽  
Peixue Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Regime ◽  
Flow Boiling ◽  
Experimental Studies ◽  
High Mass ◽  
Calculation Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Pressure Drops ◽  
Wide Range

Currently, there are no universal methods for calculating the heat transfer and pressure drop for a wide range of two-phase flow parameters in mini-channels due to changes in the void fraction and flow regime. Many experimental studies have been carried out, and narrow-range calculation methods have been developed. With increasing pressure, it becomes possible to expand the range of parameters for applying reliable calculation methods as a result of changes in the flow regime. This paper provides an overview of methods for calculating the pressure drops and heat transfer of two-phase flows in small-diameter channels and presents a comparison of calculation methods. For conditions of high reduced pressures pr = p/pcr ≈ 0.4 ÷ 0.6, the results of own experimental studies of pressure drops and flow boiling heat transfer of freons in the region of low and high mass flow rates (G = 200–2000 kg/m2 s) are presented. A description of the experimental stand is given, and a comparison of own experimental data with those obtained using the most reliable calculated relations is carried out.

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