Global moment‐independent sensitivity analysis of single‐stage thermoelectric refrigeration system

2019 ◽  
Vol 43 (15) ◽  
pp. 9055-9064 ◽  
Author(s):  
Feng Zhang ◽  
Xiayu Xu ◽  
Lei Cheng ◽  
Lu Wang ◽  
Zhongbing Liu ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Single Stage ◽  
Refrigeration System ◽  
Thermoelectric Refrigeration ◽  
Global Moment

Global sensitivity analysis of two‐stage thermoelectric refrigeration system based on response variance

2020 ◽  
Vol 44 (8) ◽  
pp. 6623-6630 ◽  
Author(s):  
Feng Zhang ◽  
Xiayu Xu ◽  
Lu Wang ◽  
Zhongbing Liu ◽  
Ling Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Global Sensitivity Analysis ◽  
Refrigeration System ◽  
Two Stage ◽  
Global Sensitivity ◽  
Thermoelectric Refrigeration ◽  
Response Variance

Thermodynamic modeling and sensitivity analysis of ejector in refrigeration system

2018 ◽  
Vol 126 ◽  
pp. 485-492 ◽  
Author(s):  
Jiapeng Liu ◽  
Lei Wang ◽  
Lei Jia ◽  
Xinli Wang
Keyword(s):  
Sensitivity Analysis ◽  
Thermodynamic Modeling ◽  
Refrigeration System

Adjoint-Based Sensitivity Analysis for Unsteady Bladerow Interaction Using Space–Time Gradient Method

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Junsok Yi ◽  
Luigi Capone
Keyword(s):  
Sensitivity Analysis ◽  
Space Time ◽  
Optimization Techniques ◽  
Single Stage ◽  
Time Dependent ◽  
Design Parameters ◽  
Engineering Practice ◽  
Multiple Time ◽  
Blade Design ◽  
Turbomachinery Design

Temporal variation of components' performance is becoming a crucial parameter in turbomachinery design process. The main physical mechanism driving the time-dependent behavior is the unsteady bladerow interaction as stator–rotor relative motion due to rotating frame of reference. However, so far unsteady effects have been ignored in design processes in common engineering practice. In fact, steady approach has been generally employed for computational fluid dynamics (CFD)-based turbomachinery design. Moreover, conventional blade design has been based on single operating point considerations. Taking into account multiple time-dependent phenomena, as the unsteady performance parameters variation, might be beneficial in making a further improvement on component performance. In quantitative terms, first of all it is important to investigate the relative effect of unsteady variation, compared to the standard steady approach, and to create a capability for calculating temporal sensitivity variation, while keeping a reasonable computing cost. This work investigates the unsteady variation of turbomachinery performance on quasi-three-dimensional (3D) geometries: single-stage turbine and single-stage compressor. Steady flow solutions using mixing plane method are compared to the unsteady flow solutions using a direct unsteady calculation, while assessing the introduction of the space–time gradient (STG) method. The results clearly show how the unsteady variation is a non-negligible effect in performance prediction and blade design. Then, a new computational technique to quantify temporal sensitivity variation is introduced, based on the STG method, with an extension to adjoint-based sensitivity analysis. The relation between time and space in multipassage-multirow domain, the fundamental assumption of the STG method, is applied within the adjoint operator formulation, which gives unsteady sensitivity information on a broad range of design parameters, at the cost of a single computation. Finally, the unsteady sensitivities are compared to the ones resulting from steady solution in the two quasi-3D cases. This work introduces a coherent and effective mathematical formulation for accounting deterministic unsteadiness on component design, while reducing computational cost compared to standard unsteady optimization techniques.

A Gradient Based Optimization Framework for the Design of Single and Multi-Stage Metal Forming Processes

2000 ◽  
Author(s):  
Akkaram Srikanth ◽  
Nicholas Zabaras
Keyword(s):  
Sensitivity Analysis ◽  
Metal Forming ◽  
Driving Forces ◽  
Single Stage ◽  
Lagrangian Analysis ◽  
Equilibrium Equations ◽  
Infinite Dimensional ◽  
Multi Stage ◽  
Gradient Based ◽  
Optimization Methodology

Abstract A gradient based optimization methodology is developed for the design of metal forming processes. A novel, efficient and mathematically rigorous scheme is proposed for a continuum based sensitivity analysis of metal forming processes that can be used to accurately evaluate gradients of the objective function and design constraints. In particular, a sensitivity analysis is being developed for the Lagrangian analysis of finite inelastic deformations of hyperelastic-viscoplastic materials involving frictional contact. A framework for shape as well as parameter optimization for single-stage metal forming processes was introduced in [1–4]. Weak sensitivity equilibrium equations were derived for the large deformation of the workpiece in a typical forming operation. This sensitivity kinematic problem was linearly coupled with the appropriate sensitivity constitutive and contact sub-problems. Thus a linear sensitivity problem with appropriate driving forces was identified and the analysis carried out in an infinite dimensional framework. This work on the design of single-stage forming processes is currently expanded to include the design of multi-stage forming processes which necessarily involve the computation of both shape as well as non-shape (parameter) sensitivities. The direct deformation and sensitivity deformation problems are implemented using the finite element method. The effectiveness of the proposed methodology is tested here with the solution of two practical design problems in single and two-stage forming processing.

Performance Investigation of Cascade Refrigeration System Using CO2 and Mixtures

2015 ◽  
Vol 23 (03) ◽  
pp. 1550022 ◽  
Author(s):  
Nourheine Jemni ◽  
Mouna Elakhdar ◽  
Ezzedine Nehdi ◽  
Lakdar Kairouani
Keyword(s):  
Single Stage ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Cascade System ◽  
Cascade Systems ◽  
High Stage ◽  
Fraction Mixture ◽  
Stage System ◽  
Vapor Compression Refrigeration ◽  
Cascade Refrigeration

This paper presents reports on simulation and comparative analysis of single stage vapor compression refrigeration system and cascade systems using carbon dioxide, hydrocarbons (HCs) and CO2/HCs mixture. Thermodynamic parameters of fluids are given using the software REFPROP 9.0. To select the most suitable HCs, three criteria have been fixed: Tc, Tt and Tb. It is found that the HCs chosen in low-stage are propane, propylene and ethane and those for the high-stage are propane, propylene and isobutane. The fraction mixture in the two loops has been varied and results are compared with single stage and cascade systems using CO2 and R22. The fraction x[Formula: see text] is varied in the two loops. Results are compared for single and cascade systems using CO2 and R22. For the single stage system, we find for xCO2 = 0.5, an improvement of COP of 14% for CO2/propane mixture and 36% for the CO2/propylene mixture. It is found that for xCO2 = 0.3, cascade system using propane/CO2 mixtures presents a COP lower than that of cascade system using pure CO2. About of 70% of unfriendly fluids like CFCs and HCFCs can be replaced with CO2, without affecting the performance of cascade refrigeration systems.

Sign in / Sign up

Export Citation Format

Share Document