Inlet Location Research Articles

Thermal challenges in heterogeneous packaging: Experimental and machine learning approaches to liquid cooling

In recent years, electronic packaging has evolved significantly to meet demands for higher performance, lower costs, and smaller designs. This shift has led to heterogeneous packaging, which integrates chips of varying stack heights and results in non-uniform heat flux and temperature distributions. These conditions pose substantial thermal management challenges, as they can create large temperature gradients, which increase thermal stress and potentially compromise chip reliability. This study explores single-phase liquid cooling for multi-chip modules (MCMs) through a comprehensive experimental and machine learning approach. It investigates the impact of chip spacing, height, fluid flow rate, fluid inlet location, and heat flux uniformity on chip temperature and the thermohydraulic performance of a commercial cold plate. Results show that increasing coolant flow from 1 LPM to 2 LPM decreased thermal resistance by 26 %, with heat losses remaining below 5 %. The left inlet configuration improved temperature uniformity compared to the right, though both yielded comparable thermal performance. Adjusting heater spacing impacted temperature distribution based on inlet position, and lowering one heater by 1 mm raised its temperatures by 15 °C due to increased thermal resistance from thermal interface material. A transient test demonstrated the cold plate’s quick response to power surges, in which there is only a 1 °C spike above steady state. Complementing these findings, an Artificial Neural Network (ANN) model was developed with optimized architecture specifically for the unique challenges of this study. The ANN model was rigorously validated using an independent dataset, achieving highly accurate temperature predictions (R2 = 0.99) within 2.5 % of experimental values, which demonstrates this framework’s potential for optimizing MCM thermal performance.

Fungal degradation of complex organic carbon supports denitrification in saturated woodchip bioreactors

Woodchip bioreactor (WBR) is a promising technology for the removal of nitrate from agricultural drainage, although the performance of WBRs is dependent on the decomposition of lignocellulosic biomass and the carbon availability for microbial denitrification. Fungal species are more efficient than bacterial counterparts in driving wood decomposition; however, little is known about the fungal community structure and functions in saturated WBRs. In this study, we investigated the dynamics of the mycobiome in field-scale, constantly saturated WBRs located in Willmar, Minnesota, USA. Fungal community analysis suggested that wood-rotting fungi were abundant in WBRs, especially near their inlet locations where microbial denitrification was most active. Complex network structures of fungal hyphae associated with a decayed cavity on the woodchip surface was further evidenced by confocal and scanning electron microscopy. These results suggest that fungi play a major role in wood degradation in WBRs, thereby promoting denitrification activity.

Structural Design and Optimization on Three‐Row J‐Type Air Cooling Channel of Pouch LiB Module

To enhance the cooling efficiency of pouch lithium‐ion battery modules, a three‐row J‐type air cooling channel structure is proposed, utilizing the previously developed multiple inlet/outlet air cooling frames. The influence of the location and number of inlets and outlets on heat dissipation performance is investigated through six air cooling channel schemes, providing a baseline for the multiobjective structural optimization of the proposed structure. Three important structural parameters, , , and l, of its air convergence and divergence plenums are selected as the design variables to improve the airflow uniformity in branch channels and minimize the pressure drop between inlets and outlets. The final design exhibits superior heat dissipation performance compared to baseline. It is noted that the airflow root mean square error in branch channels is reduced by 75.64%, while the pressure drop is increased by 19.74%. These are the critical factors for ensuring the heat dissipation performance of battery module. The maximum temperature and the maximum temperature difference of battery module are reduced by 5.29% and 23.91%, respectively, which help maintain its working temperature within a reasonable range.

Direct-supply chilled-water radiant-floor cooling system coupled with an earth‒air heat exchanger system: A case study in a building

To date, the use of shallow geothermal energy to directly cool and dehumidify a building in summer via a direct-supply chilled-water radiant-floor cooling (DS-RFC) system coupled with an earth‒air heat exchanger (EAHE) system has not been investigated. In this study, a physical test was performed in a real-world application room, where the cooling and dehumidification characteristics of DS-RFC and EAHE systems were individually studied to evaluate their application potential. The changes in the indoor air temperature and humidity and in the soil temperature when the two systems were operated independently were quantitatively analyzed. Additionally, the effects of the coupled DS-RFC/EAHE system on the indoor environment were evaluated for three air-supply inlet locations. The results showed that the DS-RFC system had a superior cooling effect but almost no dehumidification ability; the change in the humidity ratio was less than 2.00 g/kg. The EAHE system had a superior dehumidification effect, where the change in the humidity ratio exceeded 5.00 g/kg. When the DS-RFC system was operating, different air-supply inlet positions significantly affected the change states of the indoor-air state parameters. The indoor temperature was primarily concentrated at 25‒27 °C, and the relative humidity was 83‒88%. This study provides rational support for a building cooling model in which a DS-RFC system coupled with an EAHE system is supplied directly by shallow geothermal energy in summer.

An Analysis of the Ventilation Efficiency of Various Configurations of Inlet and Outlet Vents in a Residential Building by CFD Simulation

Residential buildings in South Korea have equipped an energy recovery ventilation (ERV) system to improve energy efficiency as well as dilute indoor air pollution. While most studies have focused on the efficiency of energy exchange or the ventilation performance of the ERV itself, the ventilation performance can be improved by the proper location of inlet and outlet vents. For the present study, the ventilation performance of the inlet and outlet vents of the ERV was investigated by using CFD simulation. By varying the locations of inlet and outlet vents, the airflow distributions and the age of air were assessed. In addition, the air exchange effectiveness was analyzed by using the mean age of air quantitatively. As a result, a higher age of air was observed when inlet vents were moved to the center of the plan along the wall and an additional inlet or outlet vent was installed in the kitchen. In addition, the highest air exchange effectiveness was obtained when the inlet vents were located in the center of the plan along the wall. Considering the economic perspective, it is recommended to locate the inlet vents in the center to at least improve the ventilation performance.

Performance Evaluation of a Novel Cold Plate with Double-Layer Interdigitated Flow Channels for Battery Thermal Management

Working temperature is a non-negligible factor that determines the operating performance of lithium-ion batteries which are extensively used in vehicles and the energy storage industry. Therefore, it is essential to maintain the battery temperature within an acceptable range while minimizing power consumption and ensuring uniform temperature distribution. To achieve these goals, a novel cold plate design with double-layer interdigitated flow channels is proposed in this study for efficient prismatic battery thermal management. The newly proposed cold plate design outperforms the serpentine-channel based cold plate under the same working conditions, resulting in significant improvements in both battery temperature and pressure drop. Specifically, the maximum temperature and temperature difference were reduced by over 10%, while the power cost was reduced by approximately 50%. By considering different arrangements of inlet and outlet locations, 32 non-repeating designs of the cold plate flow paths were examined. Relatively good inlet and outlet layouts are determined by comparing battery thermal management metrics including the maximum temperature, temperature difference, uniform index, and pressure drop, as well as the overall performance factors that consider both the battery temperature and power cost. In addition, the effects of the inlet flow velocity are examined to determine the optimal design.

Impact of Changing Inlet Modes in Ski Face Masks on Adolescent Skiing: A Finite Element Analysis Based on Head Models

Due to the material properties of current ski face masks for adolescents, moisture in exhaled air can become trapped within the material fibers and freeze, leading to potential issues such as breathing difficulties and increased risk of facial frostbite after prolonged skiing. This paper proposes a research approach combining computational fluid dynamics (CFD) and ergonomics to address these issues and enhance the comfort of adolescent skiers. We developed head and face mask models based on the head dimensions of 15–17-year-old males. For enclosed cavities, ensuring the smooth expulsion of exhaled air to prevent re-inhalation is the primary challenge. Through fluid simulation of airflow characteristics within the cavity, we evaluated three different inlet configurations. The results indicate that the location of the air inlets significantly affects the airflow characteristics within the cavity. The side inlet design (type II) showed an average face temperature of 35.35 °C, a 38.5% reduction in average CO2 concentration within the cavity, and a smaller vortex area compared to the other two inlet configurations. Although the difference in airflow velocity within the cavity among the three configurations was minimal, the average exit velocity differed by up to 0.11 m/s. Thus, we conclude that the side inlet configuration offers minimal obstruction to airflow circulation and better thermal insulation when used in the design of fully enclosed helmets. This enhances the safety and comfort of adolescent wearers during physical activities in cold environments. Through this study, we aim to further promote the development of skiing education, enhance the overall quality of adolescents’ skiing, and thus provide them with more opportunities for the future.

Spatter transport in a laser powder-bed fusion build chamber

The adverse effects of spatter particles are well known in laser powder-bed fusion (LPBF) additive manufacturing. To prevent the deposition of spatter particles, an inert gas flow is commonly used to transport these spatters away from the build plate. However, the inert gas flow does not remove all spatters due to varying spatter sizes and ejection angles. Therefore, it is essential to understand and predict spatter trajectories to achieve superior LPBF parts. The present study focuses on numerical modelling of spatter trajectories in Renishaw AM250 using an Eulerian-Lagrangian discrete phase model. The argon velocity profile and spatter trajectories with and against the flow are computed for various materials, sizes and ejection angles. The simulation results are validated with experimental results and show a presence of uneven flow due to inlet geometry along with varying flow profiles across the build height due to inlet location. Spatter analysis shows three methods which result in spatter deposition. Spatter particles either fall directly on the build plate, are transported by the airflow or are re-directed in the recirculation zone. The findings presented in this work indicate the importance of build chamber design along with material-based parameter optimization that results in maximum spatter removal.

Effects of inlet height of detention basins on fish movement to refuges during floods

AbstractDetention basins, typically installed adjacent to rivers, prevent the rise in water levels downstream by temporarily storing river water. Furthermore, these basins potentially promote biodiversity by creating floodplains as refuges during floods. The heights of the inlet dikes, which divert river water into the basins during floods, are designed just below the flood elevation to maximise disaster prevention. However, the accessibility of these artificial basins to organisms during floods is uncertain, primarily due to the design of the inlet dikes. Herein, we experimentally examined the effect of the height of these inlets on fish entering the detention basins during floods. The Aqua Restoration Research Center created small‐scale detention basins next to the experimental streams to induce artificial flooding using movable water gates. We controlled the height of the inlet boards to simulate an inlet dike and recorded the number of fishes that entered these basins during an experimental flood. The number of individuals moving into the basins increased as the height of the inlet board decreased. No fish were captured in the basins with the highest inlet board, which was set just below the experimental flood level. While the detention basin needs to be of a certain height of the inlet for effective flood control, we suggest a solution that may be possible to achieve both objectives, disaster prevention and biodiversity conservation, by altering the inlet location, with reference to a Japanese traditional flood reduction installation, the Kasumi‐tei.

On the variability of blocked forces determined using an inverse approach

Mount force data of motors, fans, and pumps is rarely available from the suppliers. However, manufacturers are beginning to ask for and even require this information from their suppliers. In-situ estimation of these forces can be accomplished using blocked force transfer path analysis. Since these forces are difficult to measure directly, forces are calculated using an inverse approach. A simple case study is considered on a commercial air handler. Blocked forces are determined using different inlet locations and path selections. The consistency of the inversely calculated forces is evaluated.

Influence of cyclone combustor structure on the motion behaviors of solid fuel particles

A coarse-grained computational fluid dynamics-discrete element method (CFD-DEM) was established to investigate the influence of cyclone combustor structure on the motion behaviors of solid fuel particles. Four structural parameters, i.e., primary inlet number (Pn), secondary inlet number (Sn), secondary inlet location (SL), and guide blade angle (α), were examined. Compared to the base structure with a single primary inlet, the addition of extra primary inlet, secondary inlet, or diversion structure elevates the global parcel location. Increasing Pn and Sn decreases the average parcel residence time, while augmenting SL and α generally lengthens it. Meanwhile, increasing Pn, Sn, and SL or decreasing α broadly reduces the wall parcel-hold ratio. Furthermore, the inclusion of secondary inlet and diversion structure increases the probability of small parcels occurring in the near-wall zone. These observations are helpful for optimizing the design and operation of cyclone combustors.

Lokalizacja wlotów kratek ściekowych w celu zapewnienia skutecznego odwodnienia ulic w procesie projektowania ulic i planów nawierzchni w Bułgarii

This study analyses the existing requirements and standards for determining the locations of grate inlets on streets in Bulgaria. Effective drainage in street design is essential for managing stormwater runoff and preventing urban areas from flooding during heavy rains. To choose optimal locations of grate inlets plays a crucial role in this process. Solving this task is related with designing street slopes in grading plans and designing sewer systems. This article presents an approach, based on successful practices used in the USA and Australia, by proposing a hydraulic based procedure for locating grate inlets in the design process. The technique is adopted to all Bulgarian requirements and standards. As a main criterion it is suggested to use the maximum allowable water spread on the pavement of the traffic lanes. The proposed method considers various factors, such as longitudinal and cross slope, size of grate inlet, design frequency period, intercepted and bypass flow. It starts with determination of the grate inlet locations on continuous grade, then incorporates the specific sag points in vertical curves and intersections. It can be used in the process of designing streets and their grading plans to optimize the drainage efficiency of streets in Bulgaria. It is hydraulic reasoned, very flexible, and easy to apply for different street sections with different features. Implementing this approach can solve the problem of unclarity in locating grate inlets in Bulgaria. Also, the presented procedure could be used as a base to fill gaps in the existing Bulgarian regulations and manuals, related to the drainage of streets in urban areas.

Optimizing flow uniformity and velocity fields in aquaculture tanks by modifying water inlets and nozzles arrangement: A computational fluid dynamics study

Ensuring optimal conditions for fish, especially in terms of uniform velocity fields, is crucial for aquaculture systems to attain self-cleaning efficiency in rearing tanks and better fish behavior, which ultimately impacts their survival and growth. The current study presented a full-scale computational fluid dynamics (CFD) model of three types of circular, square and square arc angle tanks used in aquaculture farms to choose the most optimal tank based on the flow uniformity and velocity field. At the next step, the optimal arrangement of the inlet number, inlet location, inlet angle, as well as the number of nozzles on each inlet was reconfigured to create the most optimal tank. The simulations were done using the CFD software FLUENT distributed by the ANSYS Corporation. The software calculates velocities in the tanks by solving the Reynolds-averaged Navier-Stokes equations of continuity and momentum that govern the mean turbulent flow of water. The results illustrated circular and square arc angle tanks had significantly more uniform fluid velocity compared to the square tanks, which the square arc angle tank due to better flow velocity near the wall and space utilization was selected for further rearrangements. Additionally, the implementation of two entrance pipes near the corner of the two parallel walls with an entry angle of 0° in a square arc angle tank resulted in a more consistent water velocity. As the number of inlet nozzles increased to six, the water streamlines became more uniform, suggesting a more consistent water velocity throughout the tank. However, when the number of input nozzles increased to nine, the tension on the nozzle apertures were increased probably due to the decrease of distance between them. Findings of the present study concluded that two inlets in the corner with an entry angle of 0° and six nozzles on each inlet pipe could provide the optimum water velocity in the square arc angle tanks.

Pseudo-transient flow path optimization of a solar tower receiver operating with supercritical carbon dioxide

Aiming to further promote the decarbonization of energy production processes, this article simulates and optimizes the pseudo-transient behavior of a cylindrical solar receiver subjected to a spatially varying concentrated heat flux. The model employed, which accounts for its thermal–hydraulic behavior, uses supercritical carbon dioxide (s-CO2) as the heat transfer fluid and is based on a literature-validated hybrid formulation that axially discretizes the tube of the receiver and simultaneously solves the 2-D temperature distribution within the cross-section of each node. The operational conditions imposed on the receiver were determined such that it can produce 10 MW in a recompression Brayton cycle. Also, the receiver’s surface was exposed to a spatially variable concentrated solar boundary condition based on the direct normal irradiance (DNI) of a representative day for each month of the year, which was selected from the typical meteorological year (TMY) in Seville (Spain). The results showed that the combined thermal–hydraulic efficiency of the receiver increases with the number of panels and that the mass flow flowing through each symmetrical side of the receiver should not necessarily be identical for achieving maximal efficiency. More importantly, the results showed that by simply changing the location of the s-CO2 inlet and outlet ports, one can increase the efficiency of the receiver by about 3 % while considering the exact same concentrated solar irradiation.

Numerical simulation and optimisation design for ventilation and heat dissipation in high-temperature and high-load indoor substations

Under high-temperature and high-load operational conditions, inadequate ventilation and suboptimal cooling arrangements within indoor substations result in high oil temperatures, posing a threat to the secure and steady operation of transformers. In this paper, the ventilation and heat dissipation effect of a 110 kV indoor substation is studied by the computational fluid dynamics method. Initially, the three-dimensional simulation model of the main transformer chamber is constructed to mirror the actual substation structure. Subsequently, the impact of the upper outlet on ventilation and heat dissipation is explored. The results show that the proximity of the upper outlet to the fan on the side wall prompts the fan to draw air from the upper outlet, diminishing the air volume entering the lower intake outlet by 38.8 %. It proves detrimental to the transformer's heat dissipation efficiency. Lastly, with the upper outlet closed, the study delves into the impact of various configurations of intake and exhaust ports on optimizing ventilation and heat dissipation. A total of six cases of two scenarios for the air inlet location and three exhaust vent positions are explored. According to the simulation results, the optimal case of substation ventilation and heat dissipation is obtained by considering four evaluation parameters.

GIS-based spatial approaches to refining urban catchment delineation that integrate stormwater network infrastructure

Rapid urbanization and escalating climate change impacts have heightened stormwater-related concerns (e.g., pluvial flooding) in cities. Understanding catchment dynamics and characteristics, including precise catchment mapping, is essential to accurate surface water monitoring and management. Traditionally, topography is the primary data set used to model surface water flow dynamics in undisturbed natural landscapes. However, urban systems also contain stormwater drainage infrastructure, which can alter catchment boundaries and runoff behavior. Acknowledging both natural and built environmental influences, this study introduces three GIS-based approaches to enhance urban catchment mapping: (1) Modifying DEM elevations at inlet locations; (2) Adjusting DEM elevations along pipeline paths; (3) Applying the QGRASS plug-in to systematically incorporate infrastructure data. Our evaluation using the geographical Friedman test (p > 0.05) and Dice Similarity Coefficient (DSC = 0.80) confirms the statistical and spatial consistency among the studying methods. Coupled with onsite flow direction validation, these results support the feasibility and reliability of integrating elements of nature and built infrastructure in urban catchment mapping. The refined mapping approaches explored in this study offer improved and more accurate and efficient urban drainage catchment zoning, beyond using elevation and topographic data alone. Likewise, these methods bolster predictive stormwater management at catchment scales, ultimately strengthening urban stormwater and flooding resilience.

Multi-objective optimization analysis of air-cooled heat dissipation coupled with thermoelectric cooling of battery pack based on orthogonal design

As the energy supply core of electric vehicles (EVs), the battery's performance is closely related to its temperature. Therefore, the battery thermal management system (BTMS) plays a crucial role in ensuring the vehicle's driving safety and power performance. This paper proposes the air cooling as the primary heat dissipation method, combined with a semiconductor refrigeration sheet (SRS) to improve heat transfer and reduce local high temperature. Firstly, determine the optimum air volume with the U-type air-cooled structure. Additionally, orthogonal analysis is used to investigate the inlet and outlet locations, the front deflector position and length of the shunt chamber, and the rear deflector position on the air-cooling effect. Then, through multi-objective optimization, the optimal air-cooled structure is selected based on the air supply pressure drop. The chosen structure is the same-side dual-exit ventilation with a front deflector located 150 mm from the near-wind end wall and a length of 30 mm, and a rear deflector located 100 mm from the far-wind end wall. Finally, SRS coupled air cooling is used to dissipate the heat. Four SRSs are used to analyze the effect of mounting position and different currents on the battery pack. The findings suggest that the optimal placement for SRSs is parallel to the lower end of the battery module at the far-wind end. When SRSs pass a current of up to 0.4A at 37 ℃, the entire battery module can complete 7200 s discharge with 0.5C. This leads to a decrease in the maximum temperature (Tmax) to 46.09 ℃ and a drop in the temperature uniformity index (δT) to 1.36.

Experimental and numerical analysis of the impact of a liquid flow rate on the operational performance of a cross-flow tube-and-fin heat exchanger

The paper is dedicated to an issue of the influence of a nonuniform flow of mediums in a cross-flow water-air heat exchanger, the core of which is a bundle of elliptical finned tubes. The main purpose of the work is to determine the impact of non-uniform water inflow for various mass flow rates on the thermal efficiency of the heat exchanger. Multivariate analyses were carried out for various temperatures of water, and for measured nonuniform air distribution at the heat exchanger input. Two variants of water distribution were considered: non-uniform water distribution assumed considering a non-uniform air inflow and water distribution resulting from hydraulic resistances calculated for different locations of water inlet and outlet nozzles. Simulation results were compared with the experimental outcomes obtained in cases of the non-uniform natural inflow of both mediums and to the computation results for a case of the uniform media inflow. The results obtained in this work confirm the significant deterioration of the thermal efficiency of heat exchangers caused by a non-uniform media inflow (by as much as 18.5% compared to the case of a uniform media inflow) which is compliant with other numerous works. The control of the water flow through the individual heat exchanger tubes enables the improvement of thermal efficiency by 4.5% to 18.6% compared to the device with uncontrolled inflow of working fluids, which for some of the analyzed cases is even better than a completely uniform inflow of heat carriers.

Effect of pocket orientation on four pocket hybrid journal bearing operating with piezo-viscous polar lubricant

PurposeThe present paper aims to analyse the synergistic effect of pocket orientation and piezo-viscous-polar (PVP) lubrication on the performance of multi-recessed hybrid journal bearing (MHJB) system.Design/methodology/approachTo simulate the behaviour of PVP lubricant in clearance space of the MHJB system, the modified form of Reynolds equation is numerically solved by using finite element method. Galerkin’s method is used to obtain the weak form of the governing equation. The system equation is solved by Gauss–Seidal iterative method to compute the unknown values of nodal oil film pressure. Subsequently, performance characteristics of bearing system are computed.FindingsThe simulated results reveal that the location of pressurised lubricant inlets significantly affects the oil film pressure distribution and may cause a significant effect on the characteristics of bearing system. Further, the use of PVP lubricant may significantly enhances the performance of the bearing system, namely.Originality/valueThe present work examines the influence of pocket orientation with respect to loading direction on the characteristics of PVP fluid lubricated MHJB system and provides vital information regarding the design of journal bearing system.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0241/

The impact of compression ratio on performance and exhaust emissions in a 100 cc spark ignition engine for green technology

The compression ratio has a significant role in vehicle performance. The arrangement of air entering and leaving the combustion chamber is determined by the design of the air inlet and outlet locations. The design of the combustion chamber is crucial to prevent backflow in the remaining combustion air. Backpressure is the emission of gases flowing back into the combustion chamber, causing non-stoichiometric combustion. The purpose of this research is to find the effect of compression ratio on performance and exhaust emissions of motorcycles, especially spark ignition engines. The research procedure begins with a standard piston modification process to get compression ratios of 9:1, 10:1, 11:1, and 12:1. In order to get uniform weight, pistons with low compression ratios will be equipped with holes at the bottom. Experimental data taken were; dynamometer, gas analyzer, and SFC. An increase in compression ratio causes an increase in vehicle performance in the form of torque and power. The air-fuel mixture is compressed to a smaller volume, leading to increased density. This increased density promotes better flame propagation and faster combustion. When the combustion process is faster and more efficient, there is less time for unburned hydrocarbons to be released into the exhaust gases.