Heat Penetration Research Articles

The impact of thermal insulation on the vulnerability of hollow masonry walls under elevated temperatures

There is little doubt that masonry walls have, throughout the history of mankind, been a critical part of building construction. From this standpoint, the present study aims to unfold the thermal behaviour of masonry walls when subjected to the standard cellulosic curve prescribed in ISO 834. Particular attention has been paid on temperature variations that are intimately connected to insulation fire resistance. The investigation initially focuses on the vulnerability of clay hollow-brick masonry wall arrangements with a varying thickness and position of insulation. These parameters are shown to significantly affect the penetration of heat through walls. In addition, temperature-dependent relationships among thermophysical properties of a combustible and a non-combustible insulation material, are examined. Alongside this, the effect of volumetric mass density on thermal conductivity for two sets of masonry units has been also taken into account. At last, this work is extended to identify the heat storage capacity of masonry walls depending on the construction arrangement of materials which can affect compartment fire dynamics. Within this framework, a numerical technique has been implemented to realise a finite element analysis (FEA) with respect to this transient thermal problem. Computational simulations have been carried out by adopting a well-known FEA modelling program.

Investigating CO2 emissions and disparity from China's central heating: A perspective at the city level

The decarbonization of China's central heating (CH) is important for reaching China's carbon peak and carbon neutrality goal. However, unclear CO2 emissions from CH of each city and their disparity hinder the formulation of targeted decarbonization strategies. To solve these issues, this study quantifies the CO2 emissions from CH in 137 cities during the period of 2006–2019 and introduces the Kaya identity and Theil index to investigate the disparity in the per capita CO2 emissions from CH. The results indicate that 1) China's CH CO2 emissions increased to 435.53 MtCO2 in 2019. Residential and public and commercial (P&C) buildings accounted for 74.18% and 25.82%, respectively. 2) The cities with the largest CH CO2 emissions of all (22.58 MtCO2), residential (16.33 MtCO2), and P&C buildings (6.86 MtCO2) were Harbin, Shenyang and Harbin, respectively. 3) The Theil index for all buildings decreased to 0.44 in 2019, and P&C buildings had the largest disparity. 4) The central heating penetration rate was the major positive contributor to the disparity of residential and P&C buildings, contributing more than 40%. In summary, at the city level, this study offers a comprehensive investigation of the CO2 emissions from CH and benefits the formulation of specific decarbonization strategies.

Simulation for charging of phase change material in existence of nanomaterial within solar energy storage system

Regarding possible solutions for thermal management of the storage unit, probably the main remedy might be to equip the system with an extended surface made from metallic materials which have high conductivity. In this study, by changing the number (n) and thickness (t1) of plates, four arrangements of the system have been suggested and solid matrix were made of three materials namely: Silicon Carbide (SiC), Aluminum (Al) and Stainless Steel (SS). Moreover, the heat absorption of phase change material (PCM) has been improved with loading of alumina nanoparticles. Increasing the number of radial plates and decreasing their thickness makes the heating penetration to increase. When the structure of geometry for SiC plates changes from (n = 5, t1 = 4 mm) to (n = 40, t1 = 0.5 mm), the melting time declines around 63.87 %. With changing the material from SS to SiC, the period of melting decreases about 66.33 % when n = 5, t1 = 4 mm. The worst case among scrutinized cases in view of speed of melting happens when n = 5, t1 = 4 mm involving Al. The best case occurs when n = 40, t1 = 0.5 mm involving SiC material and its melting time is 87.84 % lower than that of the worst case.

Magnetic non-destructive evaluation of microstructural and mechanical characteristics of hardened AISI H13 die steel upon sustainable grinding

This paper describes the potential of non-destructive techniques such as micro-magnetic Barkhausen noise (MBN) to assess the grinding burn flaws in terms of microstructural and mechanical indices of hardened AISI H13 die steel. To overcome this grinding burn issue, minimum quantity lubrication grinding with eco-friendly machining fluids like paraffin oil (PO) and castor oil (CO) was adopted and compared its performance with well-established conventional grinding like wet and dry. Ground surface integrity with castor oil (CO) was found to be significantly improvement in surface quality including lower surface roughness (Rα: 0.23 μm and Rz: 1.83 μm) with uniform surface topography, absence of oxidization and carbonization film, and negligible change in microhardness and microstructure. The reason is strong and uniform anti-friction and anti-wear tribo-film was produced by castor oil, which minimizes heat penetration through limited ploughing and rubbing action. The MBN outcome i.e., root mean square (RMS) has followed a linear relation with microhardness and temperature of the ground sample with a correlation coefficient of 0.993 and 0.981. Besides, lower amplitude and wide peak envelope get shifted towards a higher magnetic field in the MQL-CO grinding caused by poor thermal softening effect on the ground sample, which restricts magnetic domain wall movement and rotation. These outcomes could guide tooling industries for efficient sustainable grinding with faster thermal damage assessment, which helps to minimize production cycle time and back to clean environment.

Zinc hydroxystannate anchored PAP-activated carbon spheres for enhancing flame protection of aqueous epoxy coatings

Here, carbon spheres (CS), a carbonaceous spherical material with a wide source and easy preparation, were used as enhanced nano-fillers to reinforce the flame retardancy of aqueous epoxy intumescent coatings. To overcome the defects of CS themselves during combustion, polydopamine (PDA) was co-deposited with adenosine triphosphate (ATP) on its surface to obtain activated carbon spheres with C-N-P structure (CS/PAP), which can contribute to the formation of intumescent char layer. Meanwhile, zinc hydroxystannate (ZHS), as a non-halogen, environmentally friendly, and efficient flame retardant, was introduced to the surface of carbon phosphide spheres to obtain a composite functional hybrid reinforcement (CS/PAP@ZHS). Adiabatic performance tests indicated that the backside temperature of the CS/PAP@ZHS filler-reinforced EP expansion specimen was maintained at the minimum fig. (168.8 °C), confirming its highest resistance to heat penetration. Compared to the CS-based EP, the CS/PAP-loaded EP showed reduced smoke emission, indicating the effectiveness of the PAP intumescent phosphate modification for smoke suppression. By comparison, the CS/PAP@ZHS-based EP showed the largest char residue (29.1 % in N2, 12 % in air), expansion height (23.1 mm), and minimal smoke density grade (40.7 %). Additionally, compared with pure EP, the peak heat release rate (PHRR), total heat release rate (THR), peak smoke production rate (PSPR), and total smoke production (TSP) of CS/PAP@ZHS/EP are reduced by 33.3 %, 28.2 %, 37.4 %, and 23.6 % respectively, demonstrating its best fire and smoke suppression properties.

Experimental and numerical investigations on the influence of phase change materials on heat transfer reduction across the roof of a building

ABSTRACT Faced with the problems of increasing energy scarcity and ongoing environmental deterioration, phase change materials (PCM) have attracted a lot of attention recently for improving building energy performance. Utilizing the PCMs in buildings is one of the efficient approaches to reduce the heat penetration into the buildings. In this work, the thermal performance of a building equipped with PCM roof is analyzed and compared with a plain roof building. The uniqueness of this study is to analyze the effect of PCM experimentally and numerically through parametric investigation with different PCMs (HS29 and OM29), encapsulation materials (aluminum and steel) and PCM thickness. The experimental analysis shows that the PCM incorporated roof decreased the inner room temperature of the building by 2°C vis-à-vis plain roof and hence helps reduce the cooling load and enables passive cooling of the building with energy savings. A numerical analysis was carried out using COMSOL and validated with maximum and average errors of 7.43% and 4.87% respectively. The parametric investigation from the validated model indicates that the PCM OM29 is effective compared to HS29 in terms of temperature reduction. The steel encapsulating panels are observed to be better than aluminum at the peak sunshine hours while the aluminum panel is effective for the other periods. It is observed that the increase in PCM thickness augments the reduction in heat transfer while the 6 cm PCM thickness showed a higher temperature reduction by 3.6°C vis-a-vis 2 cm PCM thickness.

CFD Thermo-Hydraulic Evaluation of a Liquid Hydrogen Storage Tank with Different Insulation Thickness in a Small-Scale Hydrogen Liquefier

Accurate evaluation of thermo-fluid dynamic characteristics in tanks is critically important for designing liquid hydrogen tanks for small-scale hydrogen liquefiers to minimize heat leakage into the liquid and ullage. Due to the high costs, most future liquid hydrogen storage tank designs will have to rely on predictive computational models for minimizing pressurization and heat leakage. Therefore, in this study, to improve the storage efficiency of a small-scale hydrogen liquefier, a three-dimensional CFD model that can predict the boil-off rate and the thermo-fluid characteristics due to heat penetration has been developed. The prediction performance and accuracy of the CFD model was validated based on comparisons between its results and previous experimental data, and a good agreement was obtained. To evaluate the insulation performance of polyurethane foam with three different insulation thicknesses, the pressure changes and thermo-fluid characteristics in a partially liquid hydrogen tank, subject to fixed ambient temperature and wind velocity, were investigated numerically. It was confirmed that the numerical simulation results well describe not only the temporal variations in the thermal gradient due to coupling between the buoyance and convection, but also the buoyancy-driven turbulent flow characteristics inside liquid hydrogen storage tanks with different insulation thicknesses. In the future, the numerical model developed in this study will be used for optimizing the insulation systems of storage tanks for small-scale hydrogen liquefiers, which is a cost-effective and highly efficient approach.

Ablation resistance and mechanism of niobium carbide coatings fabricated by plasma spraying

Nb-SiC and Nb-SiC-Al system niobium carbide composite coatings were developed in-situ by plasma spraying Nb-SiC and Nb-SiC-Al system composite powders, respectively. As a comparison, NbC-Al2O3 system niobium carbide composite coating was developed ex-situ by plasma spraying NbC-Al2O3 composite powder. The ablation resistance of the three systems of niobium carbide composite coating was evaluated under plasma jet. The results showed that the Nb-SiC and Nb-SiC-Al system coatings developed in-situ have better ablation resistance than NbC-Al2O3 system coating. The microstructure of Nb-SiC and Nb-SiC-Al system coatings after different times of ablation was characterized by scanning electron microscopy to investigate the ablation mechanism. The results showed that the surface of the coating of both systems can form Nb2O5 film under ablation conditions to isolate the further penetration of oxygen and heat into the coating. The Al2O3 in the Nb-SiC-Al system coating reacted with Nb2O5 to form AlNbO4. The formation of AlNbO4 promoted the densification of Nb2O5 film, so that the Nb2O5 film formed on the surface of the Nb-SiC-Al system coating was uniform and dense, which improved the ability of the coating to resist plasma jet ablation.

A dual-domain 3 ω method for measuring the in-plane thermal conductivity of high-conductive thin films

The thermal conductivity measurement of films with submicrometer thicknesses is difficult due to their exceptionally low thermal resistance, which makes it challenging to accurately measure the temperature changes that occur as heat flows through the film. Thus, specialized and sensitive measurement techniques are required. 3ω method is a widely used and reliable tool for measuring the thermal conductivity of films. However, the high in-plane thermal conductivity in thin films results in rapid heat dissipation across the thin film, resulting in poor measurement sensitivity and making it difficult to accurately measure the temperature gradient with the traditional 3ω method. Also, the traditional 3ω method requires cross-plane thermal conductivity to derive the in-plane counterpart. Here, we introduce a dual-domain 3ω method that adopts AC-modulated heating and electrode arrays facilitating surface temperature profiling: (1) the sensitivity was significantly improved due to the employment of low-thermal-conductivity-substrate, and (2) cross-plane thermal conductivity is not required for the analysis of in-plane counterpart. This measurement platform allows us to control heat penetration in depth via varied heating frequencies as well as spatial temperature detection through laterally distributed electrodes on the thin film surface. By utilizing the described method, we have determined the in-plane thermal conductivity of a copper film, having a thickness of 300 nm, which was found to be 346 Wm−1K−1 and validated by the Wiedemann–Franz law.

Synergetic modification of graphitic carbon nitride by Zr-based metal-organic framework and tetraethoxysilane for improving fire performance in composite coatings

In this study, in an attempt to get an excellent flame retardant, herein, a new nanofiller (CNP@UiO-66@TEOS) with polyethyleneimine (PEI) as a crosslinker, Zr-based metal-organic framework (UiO-66) and tetraethoxysilane (TEOS) modified graphitic carbon nitride (CN) was synthesized. Different characterization tests confirmed the successful preparation of CNP@UiO-66@TEOS. Then, CNP@UiO-66@TEOS was doped into intumescent fire retardant (IFR) coating by solution blending method and the coating (CNP@UiO-66@TEOS/EP) was gained after curing. As expected, the CNP@UiO-66@TEOS significantly improved the fire performance of the IFR coating. The coating (CNP@UiO-66@TEOS/EP) with the addition of 2 wt% CNP@UiO-66@TEOS reduced the backside temperature by 102.9 °C over that of pure EP, proving enhanced flame retardancy. Meanwhile, CNP@UiO-66@TEOS/EP achieved the highest expansion height (21.5 mm) in the furnace experiment, contributing to a lower heat transfer ratio. In addition, the thermogravimetric analysis revealed an increase in residual char content to 31.84 wt%, which helped to resist external heat penetration. Cone calorimeter testing (CCT) showed that the peak heat release rate (PHRR), total heat release rate (THR), peak smoke production rate (PSPR), total smoke production (TSP), peak CO production rate (PCOPR), and peak CO2 production rate (PCO2PR) of CNP@UiO-66@TEOS/EP were reduced by 29 %, 19 %, 35 %, 37 %, 36 %, and 19 %, respectively, compared to pure EP, demonstrating the improved flame retardancy and smoke suppression properties. The results indicated that CN formed a thermal barrier at a high temperature and UiO-66 generated zirconium oxide (ZrO2) to catalyze the formation of residual char, thus producing a barrier effect. The TEOS on the UiO-66 surface further decomposed to form a silicon network to enhance the char layer strength of the composite. The synergistic outcome of CN, UiO-66, and TEOS offers potential avenues for the development of efficient IFR coating.

Heat source modeling, penetration analysis and parametric optimization of super spray MAG welding

Main drives, cutterheads and other critical components of tunnel shield machines require welding with thick plates that leave roots over 5 mm. Full penetration welds cannot be achieved by conventional Pulsed MAG welding methods. This article introduces Super Spray MAG Welding technology and investigates its penetrating regularities and mechanisms through high-speed camera images, finite element simulation, and microstructural analysis. An optimal welding procedure was generated using a combination of Genetic Algorithm and Back Propagation Neural Network. The data show that Super Spray MAG arc exhibits greater concentration and stability than traditional MAG arc, marking its strong qualities in emitting high-energy beams. The morphological solidification pattern of the molten pool closely matches the FEM simulation results of the composite Gaussian surface heat source model and peak linear attenuation Gaussian cylinder heat source. The welding current mainly affects the penetration of the weld, followed by the extension of the wire, and lastly the welding speed. Increasing the welding current can transition droplet transfer from globular to spray, as well as alter microstructure development and mechanical characteristics. Suggested parameters for penetrating the 5 mm root were put forward. The BPNN-GA model established can effectively predict weld formation, and points out the optimal welding parameters.

Graphene Implanted Shape Memory Polymers with Dielectric Gene Dominated Highly Efficient Microwave Drive

AbstractMicrowave‐driven strategy shows many advantages including selective energization, uniform heating, and high penetration depth, which is a hot topic in wireless actuators. Understanding microwave stimulus‐response mechanisms is the key to developing universal construction strategies for advanced microwave‐driven actuators. Herein, reduced graphene oxide (rGO) with specified dielectric genes and thermal properties is implanted into the shape memory polymer, liquid crystal elastomer (LCE) as an example, to construct soft, reversible, and sensitive microwave actuators. Based on the analysis of microstructure and dielectric properties, LCE‐rGO composites exhibit excellent polarization relaxation‐dominated dielectric loss and electromagnetic (EM) energy conversion ability. The maximum dielectric loss factor (ε″) and loss tangent (tan δe) of LCE‐rGO are dramatically increased by 216% and 87.5% compared to pure LCE, respectively, and the optimum apparent energy harvest efficiency is 19.4 times higher than that of LCE. In addition, the implantation of rGO significantly lowers the microwave actuation threshold of LCE‐rGO composites and reinforces their stimulus‐response capacity. Response time under 750 W microwave irradiation of LCE‐rGO is shortened to <10s. These findings can provide a solid basis for the design and fabrication of highly efficient microwave stimuli‐responsive polymers and enlighten a new approach to wireless actuated smart devices.

Early identification of “Gudeg” product characteristics in High Barrier Retort Grade (HBRG) packaging

Food packaging is needed to reduce the risk of food spoilage caused by physical, chemical, and biological factors. Based on the recent development, it is necessary to use a type of packaging that can be applied as food packaging while still having the durability to meet the feasibility level of the sterilization process. This study aims to identify the character of gudeg packaged with HBRG packaging procedure. In this study, the heat penetration, proximate and metal contamination analysis were done as an initial identification step for the characteristics of the gudeg in HBRG packaging. In this study, two variants of gudeg were made, namely egg gudeg and non-egg gudeg. The results obtained in this study are gudeg products packaged in HBRG packaging with a net product weight of 235 g per package. The lethality value of egg gudeg is 3.51 minutes and 4.94 minutes for non-egg gudeg. The energy value of non-egg gudeg and egg gudeg in HBRG packaging is 149.38 kcal/100g and 160.25 kcal/100g respectively. The metal contamination analysis being done in this study has stated that no heavy metal contamination was detected in all variants of products. HBRG packaging procedure can be applied for gudeg by following food safety requirements.

Engineered mycelium-based composite materials: Comprehensive study of various properties and applications

The need for increased development in sustainable materials has grown over the past few years due to the high cost and large carbon footprint of conventional materials in its production. This study highlights the possible use of mycelium as an alternative for common construction and packaging materials. Mycelium is the vegetative part of a fungi or the roots of the mushroom which can be used in producing bio-composite materials with agricultural waste (substrates) called mycelium-based composite material (MBC), whereby the mycelium acts as a natural glue binding the substrates. The oyster mushroom mycelium was used in producing MBCs with three different substrate types namely, bagasse (B + RH), coconut husk (CH + RH) and a mixture of coconut husk plus bagasse (CH + B + RH). Rice husk (RH) was added to all substrates for mycelium nutrients. Readymade and fully mycelium colonized oyster mushroom spawn in juncao grass (JG) was used as well. Four different combinations of MBCs of standard size according to ASTM D1037 standard were prepared to conduct the flexural, compressive and fire resistance tests. The results showed that B + RH and JG mycelium composites have better mycelium growth density and better flexural strength, 63.4 and 399.39 kPa, and compressive strength, 13.81 and 78.34 kPa, respectively. However, the dispersion of results for JG indicated that it had a non-homogenous growth of mycelium. Furthermore, based on the fire resistance test, B + RH performed the best as total heat penetration took more than 16 min, indicating it had low thermal conductivity than other composites and can be used as an insulating material. Other suitable end-applications have been derived for the best performing MBC, which were JG and B + RH.

PO-02-178 ABLATION TISSUE HISTOLOGY AND CORRELATION WITH MAGNETIC RESONANCE IMAGING WITH A DIAMOND-BASED, TEMPERATURE-CONTROLLED RADIOFREQUENCY ABLATION

A new catheter has been developed which uses diamonds embedded in the catheter tip to enable temperature-guided ablation. The degree to which subsequent Magnetic Resonance (MR) findings correlate with actual tissue pathology has never been assessed. To evaluate the correlation between MR imaging and lesions assessed by Gross pathology. 20 canines underwent evaluation, after ablation. 4 were studied acutely 4-6 hours after ablation, 8 animals were studied at a time of chronic assessment 4 weeks later, and 8 were studied at a time of chronic assessment 4 weeks later myocardial infarction creation. MR lesions were followed by intravenous gadolinium and 8-10% triphenyl tetrazolium chloride administration. Ex-vivo delayed contrast enhancement MR imaging on a 3 Tesla scanner (Signa HDxt, GE Healthcare) was performed followed by pathology examination after fixation in 10% formalin solution. Total of 111 lesions were created in LV and RV tissue. In the acute animals 30 deliveries were made to a temperature set-point of 50 or 60°C. The target temperatures were set at 60°C with 32 deliveries to healthy myocardium, and 8 to post-infarcted myocardium. Lesion size and characteristic are shown in table 1. The correlation between the actual lesion size and the MR contoured size is shown in Fig 1. In all animals taken together, MR proved to be an exceptional means of determining actual lesion size. While tissue histology, seen in the table, is more useful and accurate. Overall, the correlation R2 value is 0.72±0.11 (p<0.0001) in all groups. In individual groups, the correlation was 0.94±0.54 (p<0.0001) for acute, 0.48±0.13 (p<0.0001) for chronic healthy, and 0.97± 0.35 (p=0.0006) in infarcted tissue. Even with infarctions, the MR correlation remained consistent but lesions were smaller in infarcted myocardium. These data showed the characteristics of lesion size of correlation to energy delivered. MR with gadolinium is a very useful means of identifying actual lesion size in situ. This correlates well with actual tissue findings and disclose that heat penetration in infarcted tissue is less robust as seen with other catheter systems.

Numerical study of periodically heated wall effect on natural convection in an enclosure

The present numerical study focuses on sinusoidal heating and aspect ratio effects on heat flow of free convection of fluid inside the enclosure. The side walls are maintained at ambient temperature and the middle horizontal wall that divides the enclosure evenly is heated to sinusoidal temperature and the other horizontal walls are adiabatic. The numerical solution of the transport equations is done by the finite difference method to determine the heat transfer and thermal penetration with respect to aspect ratio, sinusoidal frequency and Rayleigh number. The numerical results of heat and fluid flow in the range of controlled governing parameters such as Rayleigh number (Ra = 105), sinusoidal frequency (1 ⩽N⩽ 4 ) and aspect ratio (0.2 ⩽A⩽ 4) are analysed in terms of streamlines, isotherms, heat penetration length and Nusselt number. It has been found that the 100% thermal penetration in the upper part of the enclosure of the aspect ratio A = 1 is obtained on continuous heating, while in the lower section, the maximum thermal penetration is limited to 98%, which is obtained on non-continuous heating in the enclosure of aspect ratio A = 0.2, 0.5.

Highlighting the effect of heterogeneous blood perfusion on radio-frequency ablation of human brain tumors: An image-based numerical investigation

Radio-frequency ablation (RFA) is a minimally invasive treatment that can provide highly localized and precise cancer therapy. Despite these advantages, its application in clinical practice remains limited. This is primarily due to the insufficient ablation volume, where blood perfusion plays a significant role. In this study, computational modeling is applied to examine the effects of heterogeneous blood perfusion on the tissue temperature, resultant thermal damage, and ablation volume in the RFA treatment. Two patients' heterogeneous blood perfusion and 3D brain tumor geometry are extracted from their dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data. This patient-specific information is imported into the bioheat transfer model developed in OpenFOAM to predict thermal effects. Results show that the heterogeneous blood perfusion leads to deeper heat penetration in the tumor tissue compared to the simulation in which blood perfusion is assumed to be uniform across the entire tumor. On average, the predicted tissue temperature and ablation volume are 10–11% and 30–38% higher for both patients, respectively, when the heterogeneous blood perfusion is adopted. In addition, the ablation volume is highly susceptible to the applied RF voltage and coolant temperature. These two factors can be optimized to maximize the treatment. However, the optimal settings vary for each patient, highlighting the demand for patient-specific design. Results obtained from this study can assist clinicians and surgeons in optimizing RFA parameters for a specific patient that can improve the treatment efficacy.

Comparison of reflective coating with other passive strategies: A climate based design and optimization study of building envelope

The building envelope modification in terms of insulation material, glass material, orientation, window to wall ratio (WWR), reflective coating, etc., is vital to control the heat penetration in buildings. This article evaluates the effect of Passive methods (PMs) (such as windows layers, window colors, infiltration, insulation material, insulation location in wall and roof, and orientation) in the first scenario in controlling the heat gain by building envelope for 18 cities from different Indian zones of climate. Further, the study investigated two more scenarios of passive implementation, the second scenario is a reflective roof (RR) coupled with PMs, and the third scenario is a reflective roof and wall (RRW) associated with PMs in controlling the thermal environment. The second and third scenarios also evaluated the impact of reflective surfaces on the requirement of insulation thickness for the roof and wall. This work advances the sustainability potential by optimizing critical building design parameters utilizingthe Non-dominated Genetic Algorithm (NSGA-2), which reveals a considerable reduction in required energy demand. The mean absolute percentage error (MAPE) for average hourly temperature data collected between March 14 and March 18, 2022, is 4.18 with computational results. The obtained outcomes exhibit that PMs save 6–29 % of HVAC energy annually. Where infiltration rate for all climates except cold climate is 0.2 ACH; however, cold climatic cities are perceived in the range of 0.6–0.8 ACH and 0.2–0.4 ACH for Shillong and Srinagar, respectively. It can also be stated that double-layer green 6 mm/13 mm air windows would give the best optimum solution for all climates. A coupled system of PMs and RR has demonstrated an energy savings potential of 11–32%, depending upon the climatic regions. The obtained outcomes from PMs and RR coupled systems also significantly reduced insulation thickness.

Spray coagulation as an alternative to argon plasma coagulation for bleeding portal hypertensive gastropathy

Spray coagulation as an alternative to argon plasma coagulation for bleeding portal hypertensive gastropathy

Prediction of Temperature and Viscosity Profiles in Heavy-Oil Producer Wells Implementing a Downhole Induction Heater

Very high viscosity significantly impacts the mobility of heavy crude oil representing difficulties in production and a decrease in the well’s efficiency. Downhole electric heating delivers a uniform injection of heat to the fluid and reservoir, resulting in a substantial decrease in dynamic viscosity due to its exponential relationship with temperature and a drop in frictional losses between the production zone and the pump intake. Therefore, this study predicts temperature and viscosity profiles in heavy oil-production wells implementing a downhole induction heater employing a simplified CFD model. For the development of the research, the geometry model was generated in CAD software based on the geometry provided by the BCPGroup and simulated in specialized CFD software. The model confirmed a 46.1% effective decrease of mean 12° API heavy-oil dynamic viscosity compared with simulation results without heating. The developed model was validated with experimental data provided by the BCPGroup, obtaining an excellent agreement with 0.8% and 15.69% mean error percentages for temperature and viscosity, respectively. Furthermore, CFD results confirmed that downhole electrical induction heating is an effective method for reducing heavy-oil dynamic viscosity; however, thermal effects in the reservoir due to heat penetration were insignificant. For this study, the well will remain stimulated.