scholarly journals Experimental Assessment of Thermal Performance and Bridging Effects of Low-Cost Sandwich Panels under a High-Temperature Impinging Jet

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3620
Author(s):  
Wei Ye ◽  
Jian Cai ◽  
Yixiang Huang ◽  
Chengqiang Zhi ◽  
Xu Zhang
Keyword(s):  
Thermal Performance ◽  
Low Cost ◽  
Sandwich Panels ◽  
Impinging Jet ◽  
Maximum Temperature ◽  
Aluminum Silicate ◽  
The Core ◽  
Thermal Bridge ◽  
Angle Iron ◽  
Thermal Bridges

Sandwich panels are commonly used across industries for their ability to bear structural and thermal loads. In this paper, a panel chamber matching apparatus was designed to investigate the thermal performance of eight steel-based panels by exposing them to an impinging jet at approximately 550 °C for 30 min. Three types of low-cost materials (polycrystalline filaments, silica aerogel, and aluminum silicate) were used as the insulation core. The temperature of the panel surfaces was measured, as well as the metallic fasteners, including bolts, nails, battens, seams, and angle iron, to examine their thermal bridge effects. Major conclusions include the following: first, the maximum temperature on the impinged surface was consistent among all 20 cases, whereas that of the surface under free convection varied, ranging from 41 to 120 °C, depending on the core and thermal bridges. Second, most of the highest temperatures on opposite surfaces were caused by a section of bare angle iron, and this bridging effect could be significantly reduced by up to 50 °C using a few layers of cloth, although the improvement could be temporary. Bolts and nails were less effective as thermal bridges, while the battens could be more effective. Third, the estimated heat flux of all specimens ranged from 167 to 331 W·m−2.

Impact behavior of hollow glass bubble reinforced foam core LNG insulation panel in cryogenic temperature

2020 ◽  
pp. 002199832098081
Author(s):  
Dong-Ha Lee ◽  
Jin-Ho Bae ◽  
Byeong-Kwan Hwang ◽  
Jeong-Hyeon Kim ◽  
Seul-Kee Kim ◽  
...  
Keyword(s):  
Impact Strength ◽  
Thermal Performance ◽  
Cryogenic Temperature ◽  
Sandwich Panels ◽  
Core Material ◽  
Insulation Material ◽  
Cryogenic Temperatures ◽  
Hollow Glass ◽  
The Core ◽  
Absorption Energy

Composite sandwich panels are applied to numerous structures owing to their excellent mechanical properties and thermal performance. In marine craft, sandwich panels are located on the inner walls as an insulation system for the liquefied natural gas (LNG) cargo containment systems (CCSs). Polyurethane foam (PUF), as an insulation material, is commonly used as the core material against a cryogenic temperature of –163°C for the LNG CCSs. Owing to its excellent thermal performance that prevents heat flow from the outside, and because LNG is transported at cryogenic temperatures, PUF is the preferred choice as a core material. However, the LNG CCS is subjected to fluid impact load due to sloshing during a laden voyage, and therefore, the core material needs to be reinforced. In this study, a reinforcement material made of hollow glass bubbles (HGBs) was added to PUF to help withstand the sloshing loads, and the performance of the specimens was investigated in terms of their impact strength and absorption energy. The mechanical impact strength of the final products was investigated through an impact test at cryogenic temperatures and the absorption energy was analyzed along with the dynamic compressive behavior of the sandwich panels.

Spray Cooling for Time Resolved Emission Measurements of ICs

2004 ◽  
Author(s):  
Rama R. Goruganthu ◽  
David Bethke ◽  
Shawn McBride ◽  
Tom Crawford ◽  
Jonathan Frank ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Performance ◽  
Flip Chip ◽  
Cooling System ◽  
Spray Cooling ◽  
Junction Temperature ◽  
Maximum Temperature ◽  
Uniform Heat Flux ◽  
High Heat Flux ◽  
Time Resolved

Abstract Spray cooling is implemented on an engineering tool for Time Resolved Emission measurements using a silicon solid immersion lens to achieve high spatial resolution and for probing high heat flux devices. Thermal performance is characterized using a thermal test vehicle consisting of a 4x3 array of cells each with a heater element and a thermal diode to monitor the temperature within the cell. The flip-chip packaged TTV is operated to achieve uniform heat flux across the die. The temperature distribution across the die is measured on the 4x3 grid of the die for various heat loads up to 180 W with corresponding heat flux of 204 W/cm2. Using water as coolant the maximum temperature differential across the die was about 30 °C while keeping the maximum junction temperature below 95 °C and at a heat flux of 200 W/cm2. Details of the thermal performance of spray cooling system as a function of flow rate, coolant

scholarly journals A numerical study of the impact perforation of sandwich panels with graded hollow sphere cores

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110094
Author(s):  
Ibrahim Elnasri ◽  
Han Zhao
Keyword(s):  
Boundary Conditions ◽  
Hollow Sphere ◽  
Sandwich Panel ◽  
Numerical Study ◽  
Sandwich Panels ◽  
Hopkinson Bar ◽  
Core Density ◽  
The Core ◽  
The Impact ◽  
Force Displacement

In this study, we numerically investigate the impact perforation of sandwich panels made of 0.8 mm 2024-T3 aluminum alloy skin sheets and graded polymeric hollow sphere cores with four different gradient profiles. A suitable numerical model was conducted using the LS-DYNA code, calibrated with an inverse perforation test, instrumented with a Hopkinson bar, and validated using experimental data from the literature. Moreover, the effects of quasi-static loading, landing rates, and boundary conditions on the perforation resistance of the studied graded core sandwich panels were discussed. The simulation results showed that the piercing force–displacement response of the graded core sandwich panels is affected by the core density gradient profiles. Besides, the energy absorption capability can be effectively enhanced by modifying the arrangement of the core layers with unclumping boundary conditions in the graded core sandwich panel, which is rather too hard to achieve with clumping boundary conditions.

scholarly journals Study of Mini Channel Heat Sink with Different Internal Configuration

2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed
Keyword(s):  
Nusselt Number ◽  
Thermal Performance ◽  
Heat Sink ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Rectangular Channels ◽  
Flow Through ◽  
Internal Configuration

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).

scholarly journals Thermal Behavior ofTacca leontopetaloidesStarch-Based Biopolymer

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Nurul Shuhada Mohd Makhtar ◽  
Miradatul Najwa Muhd Rodhi ◽  
Mohibah Musa ◽  
Ku Halim Ku Hamid
Keyword(s):  
High Temperature ◽  
Natural Rubber ◽  
Thermal Behavior ◽  
Thermal Performance ◽  
Palm Oil ◽  
Palm Olein ◽  
Low Cost ◽  
Thermal Testing ◽  
Crude Palm Oil ◽  
Roll Mill

Starch is used whenever there is a need for natural elastic properties combined with low cost of production. However, the hydrophilic properties in structural starch will decrease the thermal performance of formulated starch polymer. Therefore, the effect of glycerol, palm olein, and crude palm oil (CPO), as plasticizers, on the thermal behavior ofTacca leontopetaloidesstarch incorporated with natural rubber in biopolymer production was investigated in this paper. Four different formulations were performed and represented by TPE1, TPE2, TPE3, and TPE4. The compositions were produced by using two-roll mill compounding. The sheets obtained were cut into small sizes prior to thermal testing. The addition of glycerol shows higher enthalpy of diffusion in which made the material easily can be degraded, leaving to an amount of 6.6% of residue. Blending of CPO with starch (TPE3) had a higher thermal resistance towards high temperature up to 310°C and the thermal behavior of TPE2 only gave a moderate performance compared with other TPEs.

Thermal Performance Evaluation of Cork Phenolic for Nozzle External Thermal Protection System Using 250 kW Plasma Jet Facility

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
L. Aravindakshan Pillai ◽  
N. Sreenivas ◽  
K. Krishnaraj ◽  
Vinay Unnikrishnan ◽  
M. Ajith
Keyword(s):  
Thermal Performance ◽  
Thermal Protection ◽  
Plasma Jet ◽  
Thermal Protection System ◽  
Protection System ◽  
Convective Heating ◽  
Launch Vehicles ◽  
Time Of Application ◽  
The Core ◽  
Long Time

In one of the launch vehicles of ISRO, there are two solid strap-ons attached to the core liquid engine. During the ascent phase, the external nozzle divergent of the strap-ons experiences heating due to radiation from the strap-ons as well as convective heating from the impingement of plumes from the core engine. Hence, the nozzle divergent of the strap-on beyond compliance ring is thermally protected by a coating of PC10 insulation applied over carbon/epoxy structural backup. Though the system worked satisfactorily, application of PC10 had increased the inert weight of each nozzle by 165 kg and took long time for realization. To reduce the inert weight as well as the time of application, precast phenolic based cork sheets (CkP) having lower density than PC10 were selected, as a replacement to PC10. As part of evaluating the thermal performance of the CkP material, specimen level tests with different configurations were carried out in 250 kW plasma jet facility of Vikram Sarabhai Space Centre (VSSC) wherein both the heat flux and the shear stress as expected in flight were simulated simultaneously. At the end of the test program, CkP was found to be superior to PC10 for external thermal protection system (TPS). This paper highlights details of the qualification tests carried out for clearing the cork phenolic system for use in the future launches.

scholarly journals Research on Influence of Different Simulation Methods of Bypass Flow in Thermal Hydraulic Analysis on Temperature Distribution in HTR-10

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Shiyan Sun ◽  
Youjie Zhang ◽  
Yanhua Zheng
Keyword(s):  
Temperature Distribution ◽  
Reactor Core ◽  
Flow Distribution ◽  
Maximum Temperature ◽  
Flow Ratio ◽  
Hydraulic Analysis ◽  
Bypass Flow ◽  
Pebble Bed ◽  
The Core ◽  
Thermal Hydraulic Analysis

In pebble-bed high temperature gas-cooled reactor, gaps widely exist between graphite blocks and carbon bricks in the reactor core vessel. The bypass helium flowing through the gaps affects the flow distribution of the core and weakens the effective cooling of the core by helium, which in turn affects the temperature distribution and the safety features of the reactor. In this paper, the thermal hydraulic analysis models of HTR-10 with bypass flow channels simulated at different positions are designed based on the flow distribution scheme of the original core models and combined with the actual position of the core bypass flow. The results show that the bypass coolant flowing through the reflectors enhances the heat transfer of the nearby components efficiently. The temperature of the side reflectors and the carbon bricks is much lower with more side bypass coolant. The temperature distribution of the central region in the pebble bed is affected by the bypass flow positions slightly, while that of the peripheral area is affected significantly. The maximum temperature of the helium, the surface, and center of the fuel elements rises as the bypass flow ratio becomes larger, while the temperature difference between them almost keeps constant. When the flow ratio of each part keeps constant, the maximum temperature almost does not change with different bypass flow positions.

scholarly journals Quantifying Soil Compaction in Persimmon Orchards Using ISUM (Improved Stock Unearthing Method) and Core Sampling Methods

Agriculture ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 266 ◽  
Author(s):  
Ehsan Moradi ◽  
Jesús Rodrigo-Comino ◽  
Enric Terol ◽  
Gaspar Mora-Navarro ◽  
Alexandre Marco da Silva ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Soil Erosion ◽  
Bulk Density ◽  
Soil Compaction ◽  
Structural Changes ◽  
Low Cost ◽  
Positive Contribution ◽  
The Core ◽  
Core Sampling ◽  
Core Method

Agricultural activities induce micro-topographical changes, soil compaction and structural changes due to soil cultivation, which directly affect ecosystem services. However, little is known about how these soil structural changes occur during and after the planting of orchards, and which key factors and processes play a major role in soil compaction due to cultivation works. This study evaluates the improved stock unearthing method (ISUM) as a low-cost and precise alternative to the tedious and costly traditional core sampling method, to characterize the changes in soil compaction in a representative persimmon orchard in Eastern Spain. To achieve this goal, firstly, in the field, undisturbed soil samples using metallic core rings (in January 2016 and 2019) were collected at different soil depths between 45 paired-trees, and topographic variations were determined following the protocol established by ISUM (January 2019). Our results show that soil bulk density (Bd) increases with depth and in the inter-row area, due to the effect of tractor passes and human trampling. The bulk density values of the top surface layers (0–12 cm) showed the lowest soil accumulation, but the highest temporal and spatial variability. Soil consolidation within three years after planting as calculated using the core samples was 12 mm, whereas when calculated with ISUM, it was 14 mm. The quality of the results with ISUM was better than with the traditional core method, due to the higher amount of sampling points. The ISUM is a promising method to measure soil compaction, but it is restricted to the land where soil erosion does not take place, or where soil erosion is measured to establish a balance of soil redistribution. Another positive contribution of ISUM is that it requires 24 h of technician work to acquire the data, whereas the core method requires 272 h. Our research is the first approach to use ISUM to quantify soil compaction and will contribute to applying innovative and low-cost monitoring methods to agricultural land and conserving ecosystem services.

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