Inlet Air Temperature Research Articles

Degradation of Toluene via DBD: Detailed Kinetic Reaction Mechanism

The degradation of toluene via Dielectric Barrier Discharge(DBD) has been extensively studied experimentally, however, the reaction mechanism remains elusive, with a dearth of theoretical research. This paper focuses the reaction mechanism of toluene degradation by DBD, developing a detailed kinetic model that encompasses 122 species and 688 reactions. Through the inference of intermediate products from experimental, 661 reactions involving heavy species were established. Finding a lowest-energy reaction path for toluene open loops in conjunction with transition state(TS) theory. Detailed kinetic modelling was carried out to explore the factors affecting toluene degradation. The main species degrading toluene was found to be ·OH, followed by ·O. The degradation rate of toluene was substantially increased by humid carrier gas. The main degradation pathway of toluene is dehydrogenation from methyl groups, conversion to six-membered rings, five-membered rings, and finally ring-opening degradation. Simulation to explore species distribution in a reactor. Electron and excited state densities are predominantly in the intermediate region, and contaminant and carrier gas densities are predominantly in the vicinity of the electrodes. Increasing the inlet air temperature makes the plasma discharge more uniform and the toluene degradation more complete.

Impact of flue gas recirculation methods on NO emissions and flame stability in a swirling methane burner

This study investigates NOx emissions and flame stability using three flue gas recirculation methods: air-side recirculation (FGR), fuel-side recirculation (FIR), and combined recirculation (FGR + FIR). Experiments are conducted with varying combustion air inlet temperatures, recirculation ratios, and equivalence ratios for methane–air flames in a 2 kW swirl burner. Nonintrusive in-situ measurements of O2 and NO are performed using tunable diode laser absorption spectroscopy (TDLAS), an advanced measurement technology. Among the three methods, FGR exhibits the widest extinction limit, while FGR + FIR reaches similar extinction limits to FGR with the supply of preheated combustion air. FGR + FIR reduces NO emissions by up to 65 % at a lean equivalence ratio of 0.8.Numerical simulations conducted using Cantera offer valuable insights into the NOx formation mechanisms. The NO emission indices decrease by 50 % for both FGR + FIR and FGR at a recirculation ratio of 20 %. NO production primarily results from thermal NO and NNH mechanisms. Notably, reaction fluxes for the N2O-intermediate mechanism are the lowest in FGR + FIR. FGR + FIR demonstrates approximately 50 % reduction of NO emissions at a 20 % recirculation ratio under stable combustion conditions in both experiments and simulations. This study proposes FGR + FIR as the optimal recirculation method for low-NOx burners, offering effective NOx emission control and stable combustion performance.

Design and Process Considerations for Preparation of Modified Release Ivermectin and Praziquantel Tablets by Wet Granulation.

Dosage forms containing Ivermectin (IVER) and Praziquantel (PRAZ) are important combination drug products in animal health. Understanding the relationship between products with differing in vitro release characteristics and bioequivalence could facilitate generics. The goal of this study was to create granulations for each active ingredient, with similar release mechanisms, but substantially different in vitro release rates, and then compressing these granulations into tablets with differing release rates. Four granulation formulations were created: fast and modified release for PRAZ and IVER, respectively. The manufacturing process used high shear wet granulation and fluid bed drying, milling and sieving. Solid components, including the granulating agent, were blended in a high shear granulator and then water or a hydroalcoholic solution was added to activate the binder and initiate granule formation. Drying in a fluid bed with inlet air temperature set for 70°C and inlet air volume adjusted as required to maintain fluidization. Milling was performed in a cone mill and classification of final product was done using a vibratory sieve shaker with 18, 20, 40, and 60 mesh sieves. Formulations and processing approaches were successfully developed to produce a collection of PRAZ and IVER granules with differing particle size distributions and in vitro release characteristics. Differences in drug content in the classified granulations were observed and attributed to the low surface energy of PRAZ and the different approaches used to incorporate the active ingredients. The granulations were compressed via compaction simulator and the results show the monolithic tablets had four different release profiles.

Evaluating the influence of air temperature and far-infrared radiation on the physicochemical characteristics of dried rice

This study examines the impact of Far-Infrared (FIR) intensity and air temperature on rough rice properties, emphasizing the importance of optimizing these parameters to improve rice kernel quality. The research involved varying FIR power levels (0, 500, 100 Wm−2) and inlet air temperatures (30, 40, 50 °C), with results indicating that adjustments in temperature and FIR levels could reduce drying time and specific energy consumption (SEC), albeit potentially leading to increased percentage of cracked kernels (PCK) during rapid drying. Furthermore, the amylose content and viscosity of rice were found to be dramatically affected by incoming air temperature and FIR intensity. Higher temperatures and intensified FIR led to increased amylose levels resulting in greater peak and final viscosities. Moreover, dry heating affected the crystalline structure of the rice; elevated temperatures alongside FIR intensities contributed to enhanced resistance against shear forces leading to a firmer texture. To achieve optimal physicochemical properties during drying processes, it is recommended to optimize within a temperature range of 40–50 °C along with an FIR intensity of 100 Wm−2. This balance enables control over critical factors such as amylose content, PCK, SEC—all essential for producing high-quality rice products aligned with consumer preferences.

Microencapsulation using spray drying of anthoxyanins from Lannea microcarpa (African grape) fruits juice with pyrodextrin from sweet potato starch

Anthocyanins rich fruits of Lannea microcarpa (African grape) with antioxidant activity are an important food and herbal medicine in central Africa. This study sought to use response surface methodology to optimize spray drying microencapsulation of anthocyanins from L. microcarpa fruit juice, examining the influence of inlet air temperature (120—150 °C), inlet air flow rate (60—80 m3/h) and carrier agent (pyrodextrin) concentration (8 -16 g/100 g of juice), on various spray-dried powders characteristics. Moreover, the thermal stability study of L. microcarpa fruit juice powder produced at optimal process conditions was studied. The linear effect of inlet air temperature, inlet air flow rate and carrier agent concentration significantly affected the fruit powder properties (Moisture content, hygroscopicity, encapsulation efficiency) (P < 0.05), except in the case of hygroscopicity where linear effect of inlet air temperature did not. The optimum spray drying conditions to obtain the encapsulated fruit juice powder were determined as 150°C inlet air temperature, 80 m3/h inlet air flow rate and 9 g/100 g carrier agent concentration. The optimal spray dried juice powder was produced with a product yield of 72.4%, water activity of 0.281, having a poor flowability but high cohesiveness. Dynamic Vapor Sorption analysis showed sorption isotherm fitted GAB and BET models well and lower water activity (aw < 0.5) at 25 °C could be favorable for storage of L. microcarpa powders. Additionally, the stability study shown according to the degradation rate obtained that encapsulated fruit juice powder stored at 25 C exhibited greater stability with rate constant k = 0.0018 day-1 significantly lower than the same spray dried L. microcarpa juice powder stored at 35°C (k = 0.0035 day-1) (p < 0.05). These results demonstrate microencapsulation through spray drying using pyrodextrin from sweet potato was feasible for enhancing the stabilization of anthocyanins in form of powder with potential application in food and chemical industries.Graphical

Enhanced ensemble learning-based uncertainty and sensitivity analysis of ventilation rate in a novel radiative cooling building.

The rising global demand for air conditioning systems, driven by increasing temperatures and urbanization, has led to higher energy consumption and greenhouse gas emissions. HVAC systems, particularly AC, account for nearly half of building energy use, highlighting the need for efficient cooling solutions. Passive cooling, especially radiative cooling, offers potential to reduce cooling loads and improve energy efficiency. However, most studies focus on idealized conditions, neglecting the real-world variability of indoor and outdoor environments. This study proposes a novel machine learning-based ensemble stacking model to predict ventilation rates in passive cooling buildings, addressing the challenges of black-box modeling. The model's performance is improved across key metrics such as R2, RMSE, and MAE. For the first time, uncertainty and sensitivity analysis is applied to assess the impact of indoor and outdoor conditions on ventilation rates. Sensitivity analysis shows that the reference model's ventilation rate highly depends on inlet air temperature, internal temperatures at 0.1 and 0.2m, and internal wall heat flux, with optimization of these parameters having a significant impact on building performance. In contrast, the test building relies on fewer parameters, with external temperature, outlet air temperature, and net roof radiation being notable factors; as ambient temperature increases, so does the ventilation rate. The analysis reveals that uncertainties have minimal impact in the reference building, while the test building demonstrates greater sensitivity during warmer months, emphasizing the importance of accounting for seasonal variations. This research underscores the significance of optimizing key features to enhance natural cooling and ventilation, contributing to sustainable climate control solutions and providing an interpretable, robust model for predicting ventilation rates in energy-efficient buildings.

A comparative study of classical and innovative lobbed air diffusers using temperature sensors for thermal environment/comfort in vehicle cabins

Thermal comfort within a vehicle cabin is of utmost importance for both safety and user satisfaction. This study evaluates the impact of two air diffuser geometries—the classical and the innovative lobbed air diffusers—on the thermal environment within a car cabin. Experiments were conducted in an automobile-like enclosure within a climatic chamber, using a Dacia Duster dashboard and ventilation system. The system was manually controlled to vary airflow rates. Wireless temperature sensors were placed at strategic positions and levels (head, chest, knees) to monitor temperature variations over six measurement sessions with different ventilation configurations. Results show that both diffuser types effectively maintain a uniform temperature distribution across seating positions and levels. However, the innovative lobbed air diffusers demonstrated superior performance by maintaining slightly lower or comparable temperature, despite higher inlet air temperature. This suggests enhanced air mixing capability, leading to a more consistent and cooler environment, particularly advantageous during warmer conditions. This study highlights the importance of optimizing thermal comfort in vehicle cabins to improve passenger safety and comfort. Further research on long-term performance and energy efficiency is recommended to fully explore the benefits of innovative air diffusers.

Effects of temperature on flame structures and local extinctions of swirl spray flames

The effects of air inlet temperature on the flame structures and the local extinctions of n-decane swirl spray flames at constant air flow velocity were clarified by using the simultaneous planar laser induced fluorescence measurements of OH and CH2O. Results show that the blowoff limit decreases 48% as the temperature increases from 298 to 473 K. The OH and the [CH2O] × [OH] overlap are mainly distributed near the shear layer, while a small amount of formaldehyde is also observed in the outer recirculation zone (ORZ), corresponding to the low-temperature reactions. The formaldehyde intensity in the ORZ varies non-monotonically with the temperature. The non-monotonic temperature dependence of the formaldehyde intensity is governed by the competition of the droplet evaporation rate and the initial droplet size. The local extinctions of swirl spray flames can be identified by the formation of holes or breaks in the OH branches together with the accumulation of formaldehyde. It suggests that the combination of OH and CH2O is a good indicator to predict the local extinctions. The probability of the local extinctions decreases gradually with the temperature. The locations of the local extinction move downstream from 333 to 423 K; however, the local extinctions occur frequently near the flame root at 473 K. It reveals that the local extinctions near the flame root are mainly associated with the cooling effect and the perturbation effect of the flame–droplet interactions at low temperature and at high temperature, respectively.

Optimization of Spray Drying Process Parameter Condition for Theaflavin Extract from Black Tea (Camellia sinensis) Using Response Surface Methodology (RSM)

Black tea theaflavins contain high antioxidants that can be protective agents against SARS-CoV-2. The relatively good process conditions in spray drying are predicted to be able to protect and maintain the storage stability of theaflavin bioactive compounds by encapsulation. Therefore, this study aims to obtain optimum process conditions in spray drying black tea theaflavin extract. The analyzed data were interpreted using response surface methodology (RSM) with the independent variables used including spray drying inlet air temperature (100 oC, 120 oC, 140 oC) and extract to maltodextrin ratio (1:0.40; 1:0.80; 1:1.20 (v/v)). The resulting black tea powder was analyzed for theaflavin content by UV-Vis spectrophotometer (380 nm), moisture content by moisture analyzer, particle size by scanning electron microscopy (SEM), and yield. The optimum condition was reached at an inlet air temperature of 116oC and a ratio of black tea extract to maltodextrin 1:0.6627 (v/v) which resulted in R-square for yield, moisture content, and theaflavin content of 0.8946; 0.8016; 0.9324 respectively. The best theaflavin storage stability results were achieved in the seventh experiment with operating conditions of inlet air temperature 120oC and extract to maltodextrin ratio 1:0.23431 (v/v), obtained theaflavin content ranged from 0.37125% - 0.52650% from day 0 to day 30.

Numerical exploration of performance enhancement in falling film liquid desiccant cooling system using additive materials

ABSTRACT Liquid desiccant dehumidification has garnered significant attention due to its numerous benefits. This study focuses on enhancing the efficiency of liquid desiccant dehumidification through the use of modified solutions, particularly by incorporating polyvinyl pyrrolidone (PVP) as an additive. PVP is a nonvolatile, odorless, and nontoxic surfactant that was selected to enhance the dehumidification performance of the liquid desiccant system. Computational fluid dynamics was employed to investigate the dehumidification performance of falling film liquid desiccant systems. The study aims to assess the impact of PVP, solution parameters, and moist air conditions (humidity concentration, temperature, and flow rate) on dehumidification effectiveness. The specific objectives of the numerical simulation include analyzing performance metrics such as dehumidification rate and effectiveness to evaluate the enhancement in the falling film liquid desiccant cooling system. The selection of lithium chloride (LiCl) as the base solution and PVP as an additive at 0.4 wt% is highlighted as a key aspect of the study. The findings indicate that PVP significantly improves dehumidification effectiveness by reducing the contact angle of liquid solution on the surface plate and increasing the surface wetting ratio, thereby enhancing moisture transfer capacity. Optimal dehumidification performance is achieved with the combination of LiCl and PVP at the specified concentration. The study reveals that increasing solution or air inlet temperature reduces the dehumidification rate, while raising solution or air inlet concentration, velocity, or air humidity strengthens the dehumidification process. Additionally, the efficacy of dehumidification increases with solution velocity but decreases with solution intake concentration or air velocity. Overall, the results demonstrate an average relative increase of 21.6% in dehumidification rate and 17.4% in dehumidification effectiveness, underscoring the effectiveness of PVP in enhancing vapor absorption capability and overall system efficiency in Liquid Desiccant Cooling systems (LDCs). This enhancement is attributed to the reduction in surface tension of the liquid desiccant, as evidenced by the decrease in contact angle from 58.6° to 28.9°.

Performance Analysis of Desiccant Dehumidifier with an Expanded Regeneration Section

Temperature and humidity are critical parameters for maintaining the storage conditions and ensuring the post-harvest quality and shelf life of agricultural products. This study evaluates the performance of a desiccant dehumidifier under varying conditions to optimize storage environments. The relative humidity of the process air ranges from 60% to 90%, while the regeneration air temperature varies from 60°C to 80°C. The flow rates of process air and regeneration air are fixed at 350 m³/h and 760 m³/h, respectively. The relative humidity of the process air is reduced from 61%–91% at the inlet to 33.5%–48.75% at the outlet. During the experiment, the process air inlet temperature varies between 27.75°C and 36°C, while the regeneration air outlet temperature ranges from 37.75°C to 57.5°C. Performance parameters such as dehumidification effectiveness (η), moisture removal capacity (MRC), coefficient of performance (COP), and sensible energy ratio (SER) were analyzed. At 90% relative humidity and 80°C regeneration air temperature, a maximum dehumidification of 13.35 g/kg was achieved, whereas the lowest dehumidification of 5.5 g/kg was observed at 60% relative humidity and 60°C regeneration air temperature. These findings demonstrate the potential of the desiccant dehumidifier to maintain optimal temperature and humidity levels for prolonged shelf life and reduced post-harvest losses.

Optimization of Spray Drying Parameters and Wall Material Composition of Juniper (Juniperus drupacea L.) Extract Using Response Surface Methodology

The aim of this study was to produce a juniper extract powder rich in some bioactive and volatile components such as phenolics, α-pinene and d-limonene with a high yield. For this purpose, the juniper extract, which can be used in various food formulations, was spray-dried under optimized conditions. In this optimization, inlet air temperature (120°C - 180°C) in the spray drying process and the carrier composition were selected as independent variables, while dependent variables included drying efficiency and the total phenolic (TPC), and α-pinene contents of the extract powder. Response surface methodology was used to maximize product yield, TPC and volatile levels, especially α-pinene. The optimum inlet air temperature and carrier ratio were 180ºC and 15 g gum Arabic (GA) per 100 mL extract, respectively. The highest powder yield (37.92%), TPC (9.91 mg GAE/g dm powder) and α-pinene content (peak area 1.3×107) were obtained under the optimum conditions while the bulk and compressed bulk densities, TPC and antioxidant activity of the extract powder were 0.39±0.01 g/cm3 and 0.51±0.02 g/cm3, 9.89±0.27 g gallic acid equivalent (GAE)/100 g (dm) and 4.12±0.14 g Trolox® equivalent antioxidant activity (TEAC)/100 g dm, respectively. The particle size of the powder produced under optimum conditions ranged from 1.09 to 22.39 µm. Fifteen volatiles in both juniper extract and the reconstituted form of the extract powder were identified, and the major components of juniper extract were d-limonene, α-pinene and γ-muurolene.

Fabrication and Characterization of Sustained-release Eudragit RSPO Microsphere of Lornoxicam by Spray Drying Technique

Background: Lornoxicam is a potent non-steroidal anti-inflammatory drug (NSAID) with strong analgesic properties; however, its short half-life necessitates frequent administration for sustained efficacy. Objective: The objective of the present study was to identify critical formulation parameters affecting sustained release Eudragit RSPO microsphere of lornoxicam employing the concept of design of experiments. Method: The lornoxicam-loaded microspheres were prepared using a spray drying technique by optimizing the drug:polymer ratio(X1) and inlet air temperature (X2) using a 32 full factorial design. The percentage drug entrapment (Y1), percentage yield (Y2) and cumulative percentage of the drug dissolved at 18 hr (Y3) were selected as dependent variables. Microspheres were evaluated for percentage drug entrapment, mean particle size, percentage yield, in vitro drug release study and scanning electron microscopy (SEM). Result: The optimized batch showed 84.51% drug release after 18 h with significantly higher drug entrapment and percentage yield. The optimization was further verified using overlay and desirability plots. The sustained release behavior of the drug from microspheres in GIT was displayed. The predicted and observed responses for the optimized formulation were in close agreement with the release profile of the drug. Conclusion: The sustained release microspheres of lornoxicam may prove to be an effective analgesic with excellent anti-inflammatory potential.

Beer wheat residue as a probiotic carrier: physicochemical properties via fluid bed granulation (Beer wheat residue for lactic acid bacteria encapsulation).

In recent years, consumer preference for symbiotics containing live bacteria has surged, driven by the acknowledged health benefits. Wheat residue from beer brewing, rich in dietary fiber, remains an unexplored prebiotic raw material for developing vegan probiotic powdered products. Concerns about ambient conditions, dehydration and drying affecting bacterial cell viability prompt the investigation of protective agents (maltodextrin, l-arabinose, casein, whey protein, skimmed milk) and fluidized bed granulation microencapsulation for enhancing the survival rate of Lactiplantibacillus plantarum NKUST 817. The results of the study show that wheat residue, when utilized as the carrier with 10% indigestible dextrin FB06, served as the optimal protective agent. Optimal air inlet temperature (45, 55 and 65 °C) for fluidized bed granulation was investigated along with cell survival rate and probiotic powder characteristics such as moisture, water activity, hygroscopicity, solubility, bulk density and flowability. Bacteria without protective agents showed a survival rate of only 82.63-86.96%. However, the addition of 10% indigestible dextrin FB06 significantly increased in the survival rate of bacteria (granulated at 45-65 °C) to 93.52-95.18%. The microencapsulated bacteria powder exhibited low moisture (2.38-4.36%) and water activity (0.06-0.22). Powder fluidity, indicated by Carr's index (10.87-13.62) and the Hausner ratio (1.13-1.16%), demonstrated good flowability. Furthermore, the powder remained stable for 45 days, with a viable bacteria count of 7.29 log colony-forming units g-1 and a survival rate of 88.69%. This study pioneers vegan probiotic product development at the same time as addressing processing challenges to optimize strain resilience. This research stablishes wheat residue as a suitable candidate for a probiotics carrier. © 2024 Society of Chemical Industry.

Investigating hull dryer unit performance: Experiments and modeling of drying time

Hull compaction is an important waste management practice for volume reduction of hollow metallic hull waste generated in the back end of the nuclear fuel cycle. The hull waste should be totally dried of wash solution before high pressure compaction to avoid radiolysis and corrosion phenomena.[ 1 ] In the present work, the influence of various operating parameters (volumetric air flow rate, inlet air temperature, and quantity of hull waste) on the performance of a hull dryer unit has been investigated experimentally. It was observed that drying time exhibited an inverse relationship with both air flow rate and temperature. Furthermore, an increase in the mass of hull waste within the batching can led to improved dry air utilization efficiency. To enable a more comprehensive understanding of the drying process and accurate prediction of drying times, a mathematical model was formulated. A new methodology for estimating the specific surface area of randomly packed hull pieces has been presented. A comprehensive comparison of simulated data with measured exhaust air properties (mass absolute humidity, exit air temperature) and drying times was performed. The close agreement between model predictions and experimental results, with mean absolute percentage error ranging from 2.39923 to 25.21 established strong validation of the model, confirming its predictive capability. This validated model provides a robust foundation for designing future hull dryer units by enabling the calculation of optimal process parameters for various drying time requirements. The study shows that the direct contact hot air heating is a promising technique for drying of hull waste and can be accepted in fast reactor fuel cycle.

Experimental and numerical research on a C-type heat exchanger in duct air conditioner under non-uniform airflow

The indoor unit of duct air conditioner typically employs an A-type heat exchanger (HX), but non-uniform airflow within the duct significantly degrades heat transfer performance. The current study proposes a C-type HX to accommodate the non-uniform airflow better. Experiments are conducted to compare the C-type and A-type HXs under varying conditions, including air volume flow rate, air velocity non-uniformity, inlet air temperature, and condensing temperature. Results indicate that as the non-uniformity of inlet air velocity increases, the heat transfer capacity of A-type HX decreases obviously. In contrast, the C-type is insensitive to the non-uniform air velocity distribution, which consistently outperforms the A-type in terms of heat transfer capacity throughout various operating conditions. Additionally, a numerical model is developed to compare the local parameters of the two HX types. The C-type demonstrates a more uniform outlet air temperature and exhibits a heat transfer capacity that is 19.1% higher than the A-type, while maintaining the identical heat transfer area and size parameters.

Optimization of thermal environment and airflow distribution in data center with row-based cooling using the Taguchi/TOPSIS method

The short air supply distance of the row-based cooling system improved the cooling efficiency. However, the row-based coolers are closer to the racks, resulting in high-speed airflow and airflow mixing problem in the aisles. The internal structure of a row-cooled cluster is closely related to the cooling effect, and existing studies neglect the synergistic effect of multiple factors on the thermal performance of the row-based cooling system, which is still controversial about the optimal form of a row-based cooling cluster. This study analyzes and presents row-based cooling system airflow problems through large-scale field experiments and simulation. All rows' supply heat index (SHI) exceeds 0.2, and the return temperature index (RTI) exceeds 100 %, indicating a poor thermal environment in the DC. Taguchi and TOPSIS methods were used to analyze the coupling effect on the number of racks, power density, hot and cold aisle width, cooler's location, server's location, and blanking panels of the cluster's thermal environment. The optimal row-based cooling cluster structure form for different rack numbers and power density was determined. In order to optimize the air supply path of the cooler to reduce the air supply stream's collision, the effects of deflectors with different structures installed at the cooler supply and return air vents on the thermal environment were analyzed based on the optimal cluster structure. In practice, it is recommended to install deflectors of 45° with 50 mm, 75° with 30 mm, or 70 mm in the air supply vent of the cooler to create a better thermal environment. After cluster and deflector optimization, temperature uniformity, vortex airflow, and hot spots in the cluster are improved. SHI, RTI, and standard deviation of each cluster's average inlet air temperature are all closer to the ideal values.

Production of a herbal drink by spray drying of mixed purple basil extract-lemon juice; formulation, process optimization, and characterization

This article focuses on the production of an herbal drink containing the mixture of basil extract and lemon juice (65:35 (% v/v)), at inlet air temperature (IAT) (110–190 °C) as well as the concentrations of maltodextrin (MD, 0–7.5%) and gum Arabic (GA, 0–7.5%). Response surface methodology (RSM) was employed to investigate the variation of spray-dried powder attributes including moisture content (MC), water activity, water solubility, product yield, particle size, total monomeric anthocyanins (TMA), and aroma components. The optimum conditions for maximizing encapsulation efficiency and powder yield were IAT of 146 °C, 9.68% MD, and 5.32% GA. Both IAT and MD/GA ratio had a significant effect on final powder properties except for water activity. The GC-MS data revealed that the predominant aroma components in the final powder, lemon juice, and the reconstituted product were limonene and γ-terpinene; limonene; γ-terpinene, linalool, and 1.8 cineole, respectively. The results demonstrated that spray drying (SD) using GA/MD blends improved the consolidation of bioactive compounds in powdered form.

Energy-Efficiency-Oriented Spatial Configuration of VRV Outdoor Units in an Equipment Layer Under Background Wind Conditions

This study provides a spatial configuration method to improve the cooling efficiency of multiple VRV outdoor units placed on equipment layers with high floors. Relevant factors include wind parameters, the placement of multiple outdoor units, and louver. A total of 96 cases were designed. CFD simulations were used to obtain the inlet air temperature distributions of multiple outdoor units and then calculate their cooling efficiency. The results found that these factors have effects on the average cooling efficiency of outdoor units in a single row to a certain extent. The influencing degrees of these factors, from large to small, were the louver angle, wind parameters, and the placement of multiple outdoor units. When the cooling efficiency of outdoor units was maximum and the louver angle was 15°, the louvers could be oriented perpendicular to the dominant wind direction (90°) when wind speed was ≥6 m/s, and the unit spacing was 600 mm. Based on this, when the number of outdoor units was expanded in the limited space, staggered arrangements with different directions of heat exchange surfaces were a recommended optimization layout. This study provides technical support for improving the working efficiency of VRV outdoor units in an equipment layer.

The heat transfer characteristics of semi-molten wide sieving dilute phase particles between vertical heating surfaces

The high-temperature slag produced during the steelmaking process presents a significant opportunity for waste heat recovery and material utilization. Centrifugal granulation is acknowledged as an effective treatment method for managing this slag. However, the compact design of centrifugal granulation equipment poses a challenge in achieving the necessary cooling rates for high-temperature slag relying solely on gas-solid heat transfer within a confined space. This paper presents a physical model for the gas-solid two-phase interaction of an ultra-dilute high-temperature particle cluster and analyzes its heat exchange with vertical heating surfaces. The research indicates that radiative heat transfer is the primary mode of heat exchange between the particles and the heated surface, constituting more than 50 %. Moreover, heat is transferred from the particles through the air to the heated surface. Significantly, lowering the air inlet temperature and the particle velocity greatly improves the heat transfer performance and overall efficiency. Additionally, increasing the air flow rate can offset the decrease in contact thermal conductivity and radiative heat transfer that may occur due to increased spacing between the vertical tube bundle heating surfaces, thus promoting particle heat transfer. This study is crucial for guiding the improvement of heat transfer techniques for high-temperature molten particles in confined spaces.