Inlet Air Temperature Research Articles

Effect of Carrier Agents and Inlet Temperature on Physicochemical Properties of Encapsulated Carrot Coagulum Powder

Background: The carrot (Daucus carota L.) is a popular root vegetable grown throughout the world. In the present study, an attempt was made to use the carrot outgrades, which are purely rejected for aesthetic reasons, not meeting the standards based on size and shape. Further enzymes (Pectinase and Cellulase) are used to extract the carrot coagulum from carrot outgrades. Carrier agents were mixed into carrot coagulum and spray dried at three different inlet air temperatures (160, 170, and 180 °C) to encapsulate enzyme-extracted carrot coagulum. Aim: Carrots are nutritious and mainly rich in carotenoids. Often, very high losses are incurred during post-harvesting operations. A significant proportion of carrots are rejected due to bad aesthetics. Therefore, the objective of the study was to utilise such non-commercial carrot out-grades to recover carotenoids and produce encapsulated powder using spray drying. Methodology: The process of spray drying of enzymatically extracted carrot coagulum was standardised by varying carrier agents (maltodextrin and gum arabica) concentration and at different inlet temperatures. Pectinase (Pectinex Ultra SPL from Aspergillus aculeatus aqueous solution, ≥3,800 units/mL) and cellulose (Celluclast 1.5L from Trichoderma reesei aqueous solution, ≥700 units/g) were obtained from Novozymes, Bangalore. Trans-β-carotene was obtained from Sigma Chemical Company. All other chemicals used were of analytical grade. Results: All physicochemical properties were significantly affected by the carrier agents and temperature. Carotenoid content was highest (9.80%) at an inlet temperature of 170 °C with MD100. Overall moisture content was reduced, while other physical properties were enhanced when the temperature increased. Increasing the gum Arabica content showed a significant increase in moisture content and wettability time, as well as poorer physical properties. Results showed that the physicochemical and microstructural properties of encapsulated carrot coagulum powder (ECCP) were affected by inlet temperatures and carrier agents. Conclusion: Among all the spray-dried powders, the powder dried at 170 °C using maltodextrin at 15% alone had comparatively lower moisture content, good flowability, higher solubility, and less wetting time compared to other combination treatments and inlet temperatures, and thus fulfills the requirement of good quality spray-dried powders. Certainly, carrot out grades have a significant content of total carotenoids, which makes the utilisation of such material worthwhile for processing.

Analysis and optimization of thermal management system for super elliptic battery cell geometry in electric vehicles

Battery technology is the most important parameter affecting the range of electric vehicles. One of the biggest concerns in battery systems developed for electric vehicles is in particular, the temperature in the cells of lithium-ion (li-ion) batteries allows a limited degree of variation (°C) within the entire battery pack. Therefore, today’s electric vehicle research and development studies are focused on this issue. In this study, the battery systems of electric vehicles are parametrically designed with a 3D solid modeling program according to the super ellipse geometry, which offers a wide range of geometries, and the thermal management of the battery systems is realized. TM studies were done in ANSYS CFX. Air was selected as the coolant and the effect of different parameters (cell geometry, inter-cell distance, cell height, heat flux, inlet air velocity, and inlet air temperature) on the battery cell temperature was analyzed. D-Optimal experiment design was created with MATLAB. A two-alternative optimization study was carried out as constrained function local optimization and genetic algorithm optimization. Accordingly, it was observed that the battery pack gives the best thermal result when the distance between the cells increases and the inlet air temperature decreases. In addition, when the most well-known envelope type, cylindrical and rectangular prism shaped battery geometries in the literature are evaluated, it is concluded that the most ideal result is closer to the envelope type geometry.

Recurrent Neuronal Networks for the Prediction of the Temperature of a Synchronous Machine During Its Operation

This work presents the development of an adaptive thermal protection system for synchronous machines (SMs), taking into consideration the final cooling temperature and the operation point of the machine. This system aims to improve current thermal protections, which consist of a fixed alarm and trip thresholds regardless of the generator’s operating point or ambient temperature. A recurrent neural network (RNN)-based approach has been employed to predict SM temperatures during operation. Multiple tests have been conducted on a specially designed test bench. Inside the windings and iron core of the 5.5 kVA generator, multiple Pt100 sensors have been installed to train the neural network with real temperature values, enabling accurate predictions. The selected RNN model is Long Short-Term Memory (LSTM). Its inputs include electrical variables and the inlet and outlet air temperatures of the SM’s cooling system. The results show that the model accurately defines warning and trip thresholds, significantly improving thermal protection, as these thresholds are no longer fixed values. Additionally, the study suggests validating the model under cooling system failures and exploring its application in water-cooled systems. This research is supported by a patent on real-time thermal diagnostics for synchronous machines, highlighting its potential contribution to predictive maintenance and the monitoring of power generation systems.

Antimicrobial and insecticidal activity of spray dried juniper berry (Juniperus communis L.) essential oil microcapsules prepared by using gum arabic and maltodextrin.

Antimicrobial and insecticidal activity of spray dried juniper berry (Juniperus communis L.) essential oil microcapsules prepared by using gum arabic and maltodextrin.

NUMERICAL SIMULATION OF AIR COOLING PROCESSES IN A POULTRY HOUSE WITH A TUNNEL-SIDE VENTILATION SYSTEM

During the warm season, when ambient temperatures exceed +28 °C, the tunnel ventilation system is predominantly used in poultry facilities. This system effectively removes excess heat from the environment. However, under conditions of high ambient temperatures and high humidity, specialized systems are required to cool the incoming air and create a controlled microclimate within the poultry house. In ventilation systems, various types of cooling methods are employed to reduce the temperature of incoming air during the summer. Most commonly, these involve water spray systems. The core objective of this study is to conduct theoretical research on regulating heat and mass transfer processes in poultry houses, considering both internal dynamics and interactions through external barriers. This study proposes an innovative approach to cooling incoming air in poultry house ventilation systems. The method utilizes water sourced from underground wells and heat exchangers-recovery units (recuperators) to efficiently cool the incoming air. As a result of the numerical modeling, the temperature distribution within the service zone of the poultry house was determined. When heat exchangers are used, the inlet air temperature in the facility is maintained at +20 °C. The temperature increase along the length of the facility is clearly observed in the provided diagrams. The outlet temperature of the cooled air is +27.89 °C, which is attributed to heat generated by the poultry and the warming of the poultry house walls by external air. Thus, the air temperature within this cooling system does not exceed permissible limits. Analyzing the numerical modeling results at a height of 0.7 m from the floor level, it was concluded that no more than 2% of the poultry would experience discomfort under the proposed cooling system. The average air velocity is 0.83 m∙s⁻¹, and the air temperature is +23.64 °C.

Techno-Economic Analysis for the Costs of Drying Chickpeas: An Example Showing the Trade-Off Between Capital and Operating Costs for Different Inlet Air Temperatures

This study investigates the implementation of new drying schedules for chickpeas, a significant pulse, incorporating a techno-economic analysis. The research also explores the reduction in anti-nutritional factors, such as trypsin inhibitors, through fluidized-bed drying with an air recycling system. The processing cost per unit mass of chickpeas is predicted to decrease with an increasing recycling ratio, from over AUD 1.32/kg of chickpeas with no recycling down to AUD 0.0885/kg of chickpeas at a ratio of 99%. With no air recycling, the lowest inlet air temperature (40 °C) gives the lowest cost, but near the optimum recycling ratio, the highest inlet air temperature (80 °C) is best. This pattern is followed when considering equivalent carbon dioxide emissions, with the lowest emissions (over 0.259 kg CO2 (kg chickpeas)−1) corresponding to high recycling ratios and high inlet air temperatures. The use of air recycling should cause no significant challenges when implementing a drying schedule for trypsin inhibitor reduction in chickpeas.

Microencapsulation of flavored liquor by spray drying: Optimization using response surface methodology and genetic algorithm-based support vector regression

Flavored liquor microcapsules were prepared by spray drying with baijiu as the main core material, and gelatin, β-cyclodextrin, and maltodextrin as the composite wall material. The experiments were first conducted in a lab-scale spray dryer with ethanol retention as the objective function, and feed solid content, inlet air temperature, and feed rate as the influencing factors. The operating parameters were optimized using the commonly used response surface methodology (RSM) and a machine learning method of genetic algorithm-based support vector regression (GA-SVR). Subsequently, the pilot experiments were conducted in a pilot-scale spray dryer based on the optimized parameters. The qualities of products from the two dryers were evaluated. The results indicated that the ethanol retentions for the lab-scale and pilot-scale dryers were 47.78% and 46.07%, respectively. Compared with the RSM, the GA-SVR opted for a strategy of simultaneously increasing both inlet air temperature and feed rate while maintaining almost the same ethanol retention. The optimal operating parameters were determined as 35.7 wt% of feed solid content, 110 °C of inlet air temperature, and 9.5 mL·min−1 of feed rate for the lab-scale dryer and 28 mL·min−1 for the pilot-scale dryer. The microcapsules prepared by the two dryers exhibited a spherical shape with fine texture, and had a certain degree of heat resistance. The pilot-scale dried products showed slightly better flowability and lower residual water content. This work is aimed to provide a practical guidance for the machine learning method in optimizing the spray-dried microencapsulation.

Simulation of external environment of air-source heat pump cluster group for cold area heating

Abstract As an efficient and clean heating technology, air source heat pumps have been widely used in central heating in North China. A numerical simulation model of an air source heat pump cluster was established and the influence of external environment and cluster configuration on the inlet air temperature of the heat pump cluster were studied. The external environment includes wind speed and direction, while the cluster configuration includes overhead height, number of cluster, and installation direction. The simulation results show that the inlet temperature of the heat pump cluster will decrease with the increase of environmental wind speed; The inlet temperature of the heat pump cluster in the longitudinal frontside wind direction is higher than that in the other two wind directions; The inlet air temperature of the heat pump cluster will increase with the increase of the height above ground, but when the overhead height is increased again after reaching a certain height (0.5m), there will be no significant change in the inlet air temperature of the heat pump cluster; The more heat pumps there are in the cluster, the lower the inlet air temperature of the middle position heat pump is compared to the environmental temperature; In a calm state, the arrangement of the finned coil evaporator of the heat pump cluster can increase the average inlet air temperature from 269.63K of inward to 269.85K of outward.

Thermal Performance and Cost Assessment Analysis of a Double-Pass V-Trough Solar Air Heater

Solar air heating systems offer an effective alternative for reducing greenhouse gas emissions at a profitable cost. This work details the design, construction, and experimental evaluation of a novel double-pass V-trough solar air heater with semicircular receivers, which was built with low-cost materials readily available in the Mexican market. Thermal performance tests were conducted in accordance with the ANSI-ASHRAE 93-2010 standard. The results indicated a peak collector efficiency of 0.4461 and total heat losses of 8.8793 W/(m2 °C), with an air mass flow rate of 0.0174 kg/s. The instantaneous thermal efficiency varied between 0.2603 and 0.5633 with different air flow rates and an inlet air temperature close to the ambient temperature. The outlet air temperature reached 70 °C, making it suitable for dehydrating fruits or vegetables at competitive operating costs. Additionally, a second-law analysis was carried out, and the exergy efficiency was between 0.0037 and 0.0407. Finally, a Levelized Cost of Energy analysis was performed, and the result was USD 0.079/kWh, which was 31% lower than that of a conventional electric air heater system.

Improving Air Conditioning Performance With Circular Phase Change Materials Based Heat Storage

ABSTRACTThis study analyzes the impact of using single and multiple circular phase change materials (PCMs) to enhance the performance of an air‐conditioning (AC) unit. The technique involves attaching a heat exchanger containing cold energy storage PCM to the air conditioner's condenser. During the daytime, warm surrounding air is cooled and transmitted to the condenser of the air‐conditioning system. The computational study is conducted using the SST k –ω turbulence model. The air inlet temperature to the PCM is kept at 308.15 K, and the air flow rate is kept constant at 49 L/s. The findings indicate that, during the discharging process, the complete melting time for the multi‐circular PCM increases by almost 72% compared to the single‐circular PCM. Temperature contours reveal that turbulence happens in the solid zone, primarily at higher temperatures, within the PCM melting region. This suggests enhanced convection in this region. The fall in the outlet air temperature is greater for the multi‐circular PCM relative to the single‐circular PCM. The coefficient of performance (COP) increases by approximately 87.57% for the multi‐circular PCM system and 7.60% for the single‐circular PCM unit during summer. The power saved by the single‐circular PCM is about 0.3792 W for 6 h of operation, while the multi‐circular PCM saves approximately 4.3821 W.

Numerical investigation on fluid-thermal-electric performance of a thermoelectric-integrated helically coiled tube heat exchanger for coal mine air cooling

Abstract Mine cooling and refrigeration system to deal with the heat hazard is well developed, but the mine air cooler which serves as the most important terminal equipment is relatively backward. The severe heat hazard and urgent cooling demand in deep underground mines necessitate further improvement of cooling capacity and effectiveness under strict requirements such as being compact, portable, nontoxic, and no-pollution. The thermoelectric (TE) energy conversion technology has great potential in cooling and miniaturization applications, which can meet the strict requirements of the underground mine cooling devices. Yet, a research gap exists in integrating TE energy conversion technology with the traditional air-cooling heat exchanger to the best of our knowledge. In this work, a hybrid utilization of TE and the helically coiled tube heat exchanger (HCEX) is proposed for air cooling at the working face of underground mine. The advantage of the TE-integrated HCEX lies in the combination of the heat transfer enhancement effect by secondary flow induced inside the helically coiled tube and the solid-state Peltier cooling effect by the TE module positioned on the external shell wall of the heat exchanger, which can potentially improve the air-cooling capacity without occupying large space. A numerical simulation of the fluid-thermal-electric multiphysics field is performed to investigate the cooling rate and the effectiveness of the TE-integrated HCEX. Results show that additional cooling power can be effectively provided by TE. As the filling ratio (FR) of TE module on the external shell wall increases from 50 to 100%, the air-cooling capacity continuously increases, performing better than that of the conventional HCEX. The effect of air inlet temperature and inlet velocity on the cooling performance is investigated for the best design of the TE-integrated HCEX with FR of 100%. When the inlet temperature of air increases from 303.15 to 313.15 K under constant inlet velocity, the cooling rate increases and cooling effectiveness decreases. Also, the cooling rate increases and the cooling effectiveness decreases when the inlet velocity of air increases from 10 to 25 m s−1 under constant inlet temperature. Within the simulated range of air inlet conditions in this work, the maximum total cooling rate Q c,total at optimal current of 6 A for the TE-integrated HCEX results in an enhancement of 49.8 to 35.0% compared to the conventional HCEX. The maximum cooling effectiveness at optimal current of 6 A is 21.73–26.49% for the TE-integrated HCEX, which is higher than the effectiveness of the conventional HCEX of 15.74–18.24%.

Influence of Non-Uniform Airflow on Two-Phase Parallel-Flow Heat Exchanger in Data Cabinet Cooling System

The energy consumption of data center cooling systems is rapidly increasing, necessitating urgent improvements in cooling system performance. This study investigates a pump-driven two-phase cooling system (PTCS) utilizing a parallel-flow heat exchanger (PFHE) as an evaporator, positioned at the rear of server cabinets. The findings indicate that enhancing the vapor quality at the PFHE outlet improves the overall cooling performance. However, airflow non-uniformity induces premature localized overheating, restricting further increases in vapor quality. For PFHEs operating with a two-phase outlet condition, inlet air temperature non-uniformity has a relatively minor impact on the cooling capacity but significantly affects the drop in pressure. Specifically, higher upstream air temperatures increase the pressure drop by 7%, whereas higher downstream air temperatures reduce it by 7.7%. The implementation of multi-pass configurations effectively mitigates localized overheating caused by airflow non-uniformity, suppresses the decline in cooling capacity, and enhances the operational vapor quality of the cooling system.

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.

Can operational parameters impact spray-dried bacteria viability and production costs? An experimental study with autochthonous Lactococcus lactis subsp. lactis isolated from Amazonian artisanal cheese.

Can operational parameters impact spray-dried bacteria viability and production costs? An experimental study with autochthonous Lactococcus lactis subsp. lactis isolated from Amazonian artisanal cheese.

Degradation of Toluene via DBD: Detailed Kinetic Reaction Mechanism

Degradation of Toluene via DBD: Detailed Kinetic Reaction Mechanism

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

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

Study on the Dynamic Combustion Characteristics of a Staged High-Temperature Rise Combustor

Currently, steady-state analysis predominates in combustion chamber design, while dynamic combustion characteristics remain underexplored, and there is a lack of a comprehensive index system to assess dynamic combustion behavior. This study conducts a numerical simulation of the dynamic characteristics of the combustion chamber, employing a method combining large eddy simulation (LES) and Flamelet Generated Manifold (FGM). The inlet air temperature, air flow rate, and fuel flow rate were varied by 1%, 2%, and 3%, respectively, with a pulsation period of 0.008 s. The effects of nine different inlet parameter pulsations on both time-averaged and instantaneous combustion performance were analyzed and compared to benchmark conditions. The results indicate that small pulsations in the inlet parameters have minimal impact on the steady-state time-averaged performance. In the region near the cyclone outlet, which corresponds to the flame root area, pronounced unsteady flame characteristics were observed. Fluctuations in inlet parameters led to an increase in temperature fluctuations near the flame root. Analysis of the outlet temperature results for each operating condition reveals that inlet parameter fluctuations can mitigate the inherent combustion instability of the combustion chamber and reduce temperature fluctuations at the outlet hot spot.

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