Thermal Fluid-Structure Coupling for Atmospheric Entries

2011 ◽  
Author(s):  
Ojas Joshi ◽  
Pe´ne´lope Leyland
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Thermal Response ◽  
Space Vehicle ◽  
Structural Components ◽  
Fluid Structure ◽  
Coupling Techniques ◽  
Heat Loads ◽  
Transfer Mechanisms

This paper deals with the modeling of aero-thermal aspects of a space vehicle during its entry phase into an atmosphere. We treat the numerical coupling techniques between the external and internal aero-thermo-dynamics (ATD) produced by the interaction of ATD fields with the structural components. The thermal properties induced within the structure via heat transfer mechanisms of convection, conduction and radiation is taken into account presenting multi-disciplinary coupling between the aero-thermo-dynamics, the heat loads and the structural thermal response.

scholarly journals Field Test and Numerical Simulation on Heat Transfer Performance of Coaxial Borehole Heat Exchanger

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5471
Author(s):  
Peng Li ◽  
Peng Guan ◽  
Jun Zheng ◽  
Bin Dou ◽  
Hong Tian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Heat Exchanger ◽  
Flow Rate ◽  
Thermal Response ◽  
Heat Pumps ◽  
Inlet Temperature ◽  
Borehole Heat Exchanger ◽  
Ground Source Heat Pumps ◽  
Ground Source

Ground thermal properties are the design basis of ground source heat pumps (GSHP). However, effective ground thermal properties cannot be obtained through the traditional thermal response test (TRT) method when it is used in the coaxial borehole heat exchanger (CBHE). In this paper, an improved TRT (ITRT) method for CBHE is proposed, and the field ITRT, based on the actual project, is carried out. The high accuracy of the new method is verified by laboratory experiments. Based on the results of the ITRT and laboratory experiment, the 3D numerical model for CBHE is established, in which the flow directions, sensitivity analysis of heat transfer characteristics, and optimization of circulation flow rate are studied, respectively. The results show that CBHE should adopt the anulus-in direction under the cooling condition, and the center-in direction under the heating condition. The influence of inlet temperature and flow rate on heat transfer rate is more significant than that of the backfill grout material, thermal conductivity of the inner pipe, and borehole depth. The circulating flow rate of CBHE between 0.3 m/s and 0.4 m/s can lead to better performance for the system.

Role of Nanostructures in Anomalous Thermal Conductivity of Nanofluids

2014 ◽  
Author(s):  
S. M. Sohel Murshed ◽  
C. A. Nieto de Castro
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Cluster Size ◽  
Molecular Level ◽  
Positive Impact ◽  
Potential Applications ◽  
Individual Nanoparticles ◽  
Transfer Mechanisms

Nanofluids have stimulated immense research interest due to their superior thermophysical properties, heat transfer features and potential applications in numerous important fields. Role of nanostructures in heat transfer mechanisms and thermal properties particularly thermal conductivity of nanofluids has been presented and relevant studies are critically reviewed in this study. Research demonstrated that nanofluids exhibit anomalous thermal conductivity (generally higher than their base fluids) which increases with the loading of nanoparticles. Despite of some findings on positive impact of agglomeration or clustering of nanoparticles on thermal conductivity, contrary findings (negative) and argumentations are still widely accepted in the nanofluids research community. Literature results showed that while cluster size increases with concentration of nanoparticles, thermal conductivity of nanofluids decreases with increasing the cluster size. However, it is not yet well-understood how to control the morphology of the clusters of nanoparticles and how do they play role in changing the thermal properties of nanofluids. Furthermore, studies revealed that the primary shape or structures of nanomaterials also influence the properties of nanofluids. Nanofluids containing nanotubes of large aspect ratio exhibit superior thermal conductivity compared to nanofluids having nanoparticles of any other shapes. Nanorods (cylinder)-laden nanofluids showed slightly higher thermal conductivity than that of nanosphere-based nanofluids. Nevertheless, the structures of agglomerated or individual nanoparticles and their nano- or molecular-level activities in the host fluids are mainly responsible for the anomalous thermal conductivity of nanofluids.

Analysis of thermal properties and heat transfer mechanisms for polyurethane foams blown with water

2018 ◽  
Vol 132 (2) ◽  
pp. 1253-1262 ◽  
Author(s):  
Sung Woong Choi ◽  
Jae Min Jung ◽  
Hyeong Min Yoo ◽  
Sung Ha Kim ◽  
Woo Il Lee
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Polyurethane Foams ◽  
Transfer Mechanisms

Model Configuration for the Validation of Thermal-Mechanical Fluid-Structure-Interactions

2012 ◽  
Author(s):  
Matthias C. Haupt ◽  
Daniel Kowollik ◽  
Peter Horst ◽  
Reinhold Niesner ◽  
Burkard Esser ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Numerical Modelling ◽  
Hypersonic Flow ◽  
Experimental Investigations ◽  
Fluid Structure Interactions ◽  
Flow Conditions ◽  
Fluid Structure ◽  
Model Configuration ◽  
Transfer Mechanisms ◽  
Good Agreement

A simple configuration is described and used for computational and experimental investigations including thermal and mechanical fluid structure interactions for hypersonic flow conditions. The numerical modelling includes all relevant heat transfer mechanisms, takes into account the changes due to the heated and deformed structure and shows a good agreement with experiments.

Heat Transfer Mechanisms for Condensation and Vaporization Inside a Microfin Tube

2002 ◽  
Vol 9 (1) ◽  
pp. 25-37 ◽  
Author(s):  
Davide Del Col ◽  
Ralph L. Webb ◽  
Ram Narayanamurthy
Keyword(s):  
Heat Transfer ◽  
Transfer Mechanisms

Temperature Rise Times in Pneumatic Tires

1976 ◽  
Vol 4 (3) ◽  
pp. 181-189 ◽  
Author(s):  
S. K. Clark
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Temperature Rise ◽  
Thermal Equilibrium ◽  
Transfer Coefficients ◽  
Pneumatic Tire ◽  
Heat Transfer Coefficients ◽  
Idealized Model ◽  
Pneumatic Tires

Abstract An idealized model is proposed for heating of a pneumatic tire. A solution is obtained for the temperature rise of such a model. Using known thermal properties of rubber and known heat transfer coefficients, the time to reach thermal equilibrium is estimated.

scholarly journals Continental vs. Global Niche-Based Modelling of Freshwater Species’ Distributions: How Big Are the Differences in the Estimated Climate Change Effects?

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 816
Author(s):  
Danijela Markovic ◽  
Jörg Freyhof ◽  
Oskar Kärcher
Keyword(s):  
Climate Change ◽  
Thermal Properties ◽  
Safety Margin ◽  
Thermal Response ◽  
Future Climate Change ◽  
Freshwater Species ◽  
Response Curves ◽  
Preferred Temperature ◽  
Continental Scale ◽  
Management Actions

Thermal response curves that depict the probability of occurrence along a thermal gradient are used to derive various species’ thermal properties and abilities to cope with warming. However, different thermal responses can be expected for different portions of a species range. We focus on differences in thermal response curves (TRCs) and thermal niche requirements for four freshwater fishes (Coregonus sardinella, Pungitius pungitius, Rutilus rutilus, Salvelinus alpinus) native to Europe at (1) the global and (2) European continental scale. European ranges captured only a portion of the global thermal range with major differences in the minimum (Tmin), maximum (Tmax) and average temperature (Tav) of the respective distributions. Further investigations of the model-derived preferred temperature (Tpref), warming tolerance (WT = Tmax − Tpref), safety margin (SM = Tpref − Tav) and the future climatic impact showed substantially differing results. All considered thermal properties either were under- or overestimated at the European level. Our results highlight that, although continental analyses have an impressive spatial extent, they might deliver misleading estimates of species thermal niches and future climate change impacts, if they do not cover the full species ranges. Studies and management actions should therefore favor whole global range distribution data for analyzing species responses to environmental gradients.

scholarly journals Multidisciplinary Approaches for Assessing a High Temperature Borehole Thermal Energy Storage Facility at Linköping, Sweden

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4379
Author(s):  
Max Hesselbrandt ◽  
Mikael Erlström ◽  
Daniel Sopher ◽  
Jose Acuna
Keyword(s):  
Thermal Properties ◽  
High Temperature ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Thermal Response ◽  
Site Investigation ◽  
Thermal Response Test ◽  
Response Test ◽  
Crystalline Bedrock

Assessing the optimal placement and design of a large-scale high temperature energy storage system in crystalline bedrock is a challenging task. This study applies and evaluates various methods and strategies for pre-site investigation for a potential high temperature borehole thermal energy storage (HT-BTES) system at Linköping in Sweden. The storage is required to shift approximately 70 GWh of excess heat generated from a waste incineration plant during the summer to the winter season. Ideally, the site for the HT-BTES system should be able to accommodate up to 1400 wells to 300 m depth. The presence of major fracture zones, high groundwater flow, anisotropic thermal properties, and thick Quaternary overburden are all factors that play an important role in the performance of an HT-BTES system. Inadequate input data to the modeling and design increases the risk of unsatisfactory performance, unwanted thermal impact on the surroundings, and suboptimal placement of the HT-BTES system, especially in a complex crystalline bedrock setting. Hence, it is crucial that the subsurface geological conditions and associated thermal properties are suitably characterized as part of pre-investigation work. In this study, we utilize a range of methods for pre-site investigation in the greater Distorp area, in the vicinity of Linköping. Ground geophysical methods, including magnetic and Very Low-Frequency (VLF) measurements, are collected across the study area together with outcrop observations and lab analysis on rock samples. Borehole investigations are conducted, including Thermal Response Test (TRT) and Distributed Thermal Response Test (DTRT) measurements, as well as geophysical wireline logging. Drone-based photogrammetry is also applied to characterize the fracture distribution and orientation in outcrops. In the case of the Distorp site, these methods have proven to give useful information to optimize the placement of the HT-BTES system and to inform design and modeling work. Furthermore, many of the methods applied in the study have proven to require only a fraction of the resources required to drill a single well, and hence, can be considered relatively efficient.

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