Intake Flow Rate Research Articles

Performance investigations of cross flow indirect evaporative cooler

Dew point evaporative cooler is an indirect evaporative cooling (IEC) technique to lower temperature of incoming air below its wet bulb temperature and near to dew point temperature. The said technique does not involve any change in moisture content of incoming air. Performance parameters of dew point evaporative cooler are significantly influenced by configuration and structural arrangement of heat exchanger. The different arrangements of heat exchangers commonly used are counterflow, cross flow and counter-cross flow. This work presents performance investigations of cross flow indirect evaporative cooler. The cooling efficiencies and temperatures at the outlet of the cooler were investigated for different intake air temperatures and flow rates. Dew point evaporative cooling technique does not make use of compressor and harmful refrigerants hence would be a better option to conserve the environment and helps to reduce the emission of greenhouse gases.

Improvements on performance and emissions of a heavy duty diesel engine by throttling degree optimization: A steady-state and transient experimental study

Heavy duty diesel engines emit over half of mobile source NOx, so SCR is used to reduce NOx. But in applications, SCR is hard to work in desired temperature range. In this work, we try to improve exhaust thermal management and finally reduce NOx through intake throttling effect. Firstly a throttle was designed and its response characteristics were widely explored through steady-state experiment. Results showed that exhaust temperature can be raised largely through intake throttling degree (TD) control, it has obvious effect only after 60 % TD. At 1100 r/min and 65 % TD, exhaust temperature rises by 123.3 °C, 74.2 °C, 49.7 °C and 33.5 °C for 600 N·m, 400 N·m, 200 N·m, and 50 N·m loads, respectively. TD demand for rising transition point becomes larger as engine load decreases, at 600 N·m transition point occurs at 61 % TD, but it increases to 68 % TD at 50 N·m. Finally the intake flow rate was optimized continuously with whole cycle level consideration in transient operation. NOx decreased by 43 % with fuel consumption and HC keeping unchanged, while CO increased by 24.6 %. We hope to provide a good example for diesel engine performance improvement from optimization of existing technologies without too much cost.

Zinc Plasma Status and Sensory Perception in Nondialysis Chronic Kidney Disease Patients

The aim of this study was to evaluate the association between zinc plasma levels and sensory perception in patients with chronic kidney disease (CKD). A cross-sectional study with 21 nondialysis CKD patients (11 men, 51.1±7.1years, body mass index 27.9±7.1kg/m2, estimated glomerular filtration rate 32.7±19.9mL/min) and 22 non-CKD volunteers (10 men, 49.8±8.3years, body mass index 28.5±5.4kg/m2) was conducted. Blood samples were collected to obtain plasma for zinc analysis. Anthropometric and biochemical parameters, as well as food intake and salivary flow rate, were also evaluated. Taste sensory perception for sweet, acidic, bitter, and salty flavors was determined by the "three-drop method," with 4 concentrations of the 4 basic tastes. As expected, zinc plasma levels were significantly lower in CKD patients (70.1±19.2ug/dL) when compared with the control group participants (123.2±24.6 μg dL) (P ˂ .0001). The bitter taste perception was lower in the CKD group (p˂0.0001). Our findings showed that sensitivity to sour (P=.047), salty (P=.03), and bitter tastes was significantly lower in participants with lower zinc plasma levels. Also, bitter taste sensitivity was lower in participants with less zinc intake (P=.038). When grouping control subjects and CKD patients, significant correlations were observed between zinc plasma levels and the number of correct answers for bitter taste (r=0.49, P=.001), number of correct answers for salty taste (r=0.30, P=.048), and total score of correct answers (r=0.30, P=.044). Reduced zinc plasma levels in nondialysis CKD patients may be associated with lower perception of bitter, sour, and salty tastes and strategies to restore these levels are crucial due many factors, including food preferences and intake.

Assessment on rack intake flowrate uniformity of data center with cold aisle containment configuration

The present paper investigates the rack intake flowrate uniformity in a simulated container data center subject to cold aisle containment (CAC) configuration. Based on a novel flowrate uniformity index (FUI) in prior study, a strong flowrate mal-distribution at the rack inlets is observed by examining the standard deviation of FUI (σFUI). When raising the supplied volumetric flowrate from 2.52 m3 s−1 to 3.40 m3 s−1, the outlet temperature of each cabinet is remarkably reduced. Meanwhile, applying a gradient fan speed for cabinets can reduce the σFUI by 19.5–34.0%. However, the mal-distribution for the top and bottom cabinets is still prominent. In essence, adding air supply flowrate or changing rack intake layout show limited improvements and may even have potentially deleterious effects. To tailor the mal-distribution problem, a novel configuration featuring the concept of Coanda effect is proposed. A triangular deflector is implemented to guide the cold air sweeping through fan trays in front of the data rack. The σFUI can be effectively reduced by about 51.3–62.0% compared to the original design, showing a significant improvement on the intake flowrate distribution for all racks.

Particulate and gaseous emissions from a direct-injection spark ignition engine fueled with bioethanol and gasoline blends at ultra-high injection pressure

In this study, the effects of bioethanol mixing with gasoline on the emission of particulates and gaseous emissions at ultra-high pressure injection up to 50 MPa were investigated in a gasoline direct-injection (GDI) engine. A 398 cc single-cylinder engine fueled with bioethanol blends was used for the experiment. The gaseous emission was measured by an emission bench, and particle number (PN) was counted by a PPS-M device. Experiments were carried out under the conditions of maximum injection pressure of 50 MPa and constant intake flow rate with various injection conditions. Gasoline and bioethanol-blended fuel was used, with the blending ratio varied from 10% to 50% by volume. The results indicated that, as the injection pressure and bioethanol content increased, the PN decreased by 93.6% and 78.9%, respectively. PN emission is proportional to bioethanol contents in case of PN emitted from wall film. Effect of bioethanol addition with ultra-high pressure injection over 35 MPa is not significant on PN, since atomization enhancement due to the increased injection pressure is saturated. Total hydrocarbon and nitrogen oxide emissions decreased up to 34.5% and 35.6% with increasing oxygenated fuel, bioethanol, contents at ultra-high pressure injection over 35 MPa and were remarkably influenced by injection timing.

CFD Investigation of Airflow Management in a Small Container Data Center

In this paper, the cooling performance of a small container data center is numerically investigated. It is indicated that adjusting the plenum depth and placing baffles in the plenum can improve the airflow uniformity efficiently. On the other hand, the perforated tiles with low porosity of 25% also can significantly improve the air flowrate distribution by 88.9% with the severe pumping power penalty of 2.79 times. Hence, the layout of perforated tiles with nonuniform porosities is optimized with the fixed average porosity of 50%, which can obtain almost absolutely uniform flowrate distribution in the cold aisle. In addition, the cold aisle containment (CAC) strategy is implemented, resulting in the improved rack cooling index (RCI) and supply heat index (SHI) to approach to 100% and 0%, respectively. However, the intake flowrates still suffer from nonuniformity due to the bypass effect, thus a novel criterion named flowrate uniformity index (FUI) is proposed. Besides, the drawer-type layouts with the shifting distance ( $\delta$ ) varying from 0 to 200 mm are investigated, and the case with $\delta = 150$ mm shows the best improvement in terms of the standard deviation of FUI ( $\sigma _{\mathrm {FUI}}$ ). Moreover, the $\sigma _{\mathrm {FUI}}$ of the case with a three-layer drawer-type layout can be further improved by 45.8%.

Abstract P106: Elevated Fasting Glucose and Proteinuria in Offspring Born to Gestational Hypertensive African Green Monkeys

Preeclampsia (PreE), or gestational hypertension (GH) concurrent with proteinuria, is a leading cause of maternal and fetal mortality worldwide. PreE often leads to fetal growth restriction resulting in low birth weight offspring. Low birth weight infants are at higher risk of developing cardiovascular disease later in life. The African Green Monkey (AGM; Chlorocebus aethiops sabaeus ) develops spontaneous GH with proteinuria and fetal growth restriction. We hypothesize that GH will developmentally program offspring to reduced kidney function and metabolic disease. Maternal systolic arterial pressure (SAP) was measured via forearm plethysmography prior to pregnancy and during the 3 rd trimester of pregnancy. At 1-3 years of age, offspring were single-housed for water intake and urine flow rate collections followed by blood pressure measurement and venous blood sampling. Animals were grouped by pregnancy phenotype. SAP for normotensive (NT, n=23) mothers did not change in pregnancy, but increased during third trimester for GH (Δ=35 ± 7 mmHg, n=34). NT pregnancies resulted in a 4% stillbirth rate (1/23) compared with 29% in GH (10/34). Surviving GH offspring had reduced birth weight (NT 336 ± 11g vs. GH 295 ± 8g, p<0.05). Fasting glucose was higher in progeny born to GH pregnancies (NT 69 ± 8 mg/dl, n=13; GH 92 ± 6 mg/dl, n=20). Urinary protein excretion was higher in offspring born to GH pregnancies (NT 152 ± 27 mg/day; GH 318 ± 46 mg/day). SAP of offspring was similar between maternal phenotype (NT 107 ± 8 mmHg; GH 109 ± 5 mmHg). Juvenile SAP was unrelated to fasting glucose or urinary protein excretion, indicating that these factors are determined by maternal SAP during pregnancy, rather than juvenile phenotype. Thus, GH is associated with fetal growth restriction in the form of high stillbirth rates and lower surviving-offspring birth weights in the AGM. GH offspring have elevated fasting glucose and possible decreased kidney function as evidenced by proteinuria. GH could be programming offspring for early life metabolic risk factors and declining renal function. Future studies include oral glucose tolerance tests and additional markers of renal dysfunction to further assess in utero programming of the pathogenesis of cardiovascular and metabolic disease.

Low temperature, medium temperature and high temperature performance of the continuous regenerative diesel particulate filter assisted by electric regeneration

A model is established to investigate low temperature (<300 °C), medium temperature (300–550 °C) and high temperature (>550 °C) performance of the continuous regenerative diesel particulate filter (CR-DPF) assisted by electric regeneration regarding to balance point temperature, regeneration speed and outlet temperature respectively and relevant influencing factors. Results show that inlet PM concentration and inlet flow rate are positively correlated to balance point temperature and vice versa for initial soot loading and intake NOX concentration. Increasing intake NOX concentration and flow rate increase rapid continuous regeneration speed. At low and medium temperatures, rapid thermal response tends to increase passive regeneration speed and the trend is more with decreasing wall thickness and channel density. In the high temperature range, outlet temperature increases and temperature gradients presented in the early stage of regeneration become steeper with decreasing channel density and wall thickness. However, “L/D” has limited impact on low, medium and high temperature performance.

Modeling intraphase and interphase mass transfer limitations for NH3–SCR over Cu–ZSM–5

A model describing NH3 selective catalytic reduction (NH3-SCR) over Cu-ZSM-5 to investigate the effects of intraphase and interphase mass transfer on standard SCR reaction is developed and further verified with the synthetic gas bench. The correlation between tortuosity and porosity has been analyzed by least squares method and applied to the sinuousoidal capillary bundle model. The effects of washcoat thicknesses, lengths, cell densities and channel widths on the standard SCR reaction are analyzed in temperature range of 150–500 °C. It is found that deNOx efficiency is affected by intraphase diffusion limitations at 200–500 °C and by interphase mass transfer limitation at intermediate (250–400 °C) and high temperatures (400–500 °C). As the temperature increases, the reaction is firstly controlled by kinetics, with the kinetics resistance decreasing and then increasing until the maximum among three processes. Furthermore, intake flow rates (GHSVs) play an important role impacting NO conversion on NH3–SCR.

A statistical model for dew point air cooler based on the multiple polynomial regression approach

Swift assessment of evaporative cooling systems has become a necessity in practical engineering applications of this advanced technology. This paper bypasses details of the performance process and pioneers in developing a statistical model based on the multiple polynomial regression (MPR) to predict the performance of a dew point cooling (DPC) system. Thousands of numerical and experimental data are explored and the statistical model is produced. The developed statistical model correlates the performance parameters with the key operational parameters, including the flow and geometric characteristics. The selected operational parameters are, intake air conditions, including temperature, relative humidity and flow rate as well as the working air fraction over the intake air, while cooling capacity, coefficient of performance (COP), pressure drop, dew point and wet-bulb effectiveness are selected as performance parameters. The considered geometric characteristics are channel height, channel interval and number of layers in heat and mass exchanger. The model with different polynomial degrees is assessed by R2, MRE and MSE metrics. The 8th degree polynomial model is selected. The maximum relative error of the cooling capacity, coefficient of performance, pressure drop, dew point and wet-bulb effectiveness are 6.1%, 7.54%, 0.07%, 3.54% and 2.53% respectively. Finally, as examples, the model is used to predict the performance of the DPC system in random operating conditions and in a dry climate i.e. Las Vegas. Model developed in this study would enable the swift prediction of the DPC system.

Testosterone Reduces mRNA Expression of Renal Sodium Transporters but does not Affect Blood Pressure During a Ten‐Day Angiotensin II Infusion Period in Castrated Mice

Sex differences in blood pressure regulation are well known and it is widely accepted that premenopausal females are protected from hypertension and cardiovascular disease compared to age‐matched males. Despite extensive investigation, the effects of sex steroids on blood pressure and renal sodium handling remain debated. The purpose of this study was to determine the effects of testosterone administration on angiotensin II (Ang II) – induced increase in blood pressure and other physiological effects in castrated mice. Four‐week‐old CD‐1 castrated mice were obtained from Envigo Inc. (Indianapolis, IN) and placed in metabolic cages for a five‐day baseline period followed by implantation of an Alzet osmotic pump containing either vehicle or Ang II (1μg/kg/min) and either a placebo or 2.5 mg testosterone‐acetate pellet (Innovative Research of America, Sarasota, FL). Measurements were recorded daily in the five‐day baseline and ten‐day post‐implantation periods in three groups of mice: vehicle‐placebo (V‐P), Ang II‐placebo (Ang II‐P), and Ang II‐testosterone (Ang II‐T) (n=4/group). Mice consumed standard chow and water ad libitum throughout the study. Systolic blood pressure (SBP, mmHg) was determined daily with the tail‐cuff technique (Kent Scientific, Torrington, CT). At the end of the study, mice were sacrificed, kidneys were removed, and cortical tissue samples were processed for real‐time qtPCR to compare mRNA expression in fold difference (FD) of key sodium transporters. Ang II significantly increased blood pressure. The delta SBP (baseline vs Ang II periods) was not different between the Ang II‐P and Ang II‐T groups: (27.0 ± 4.5 vs 31.1 ± 5.9, respectively), and these values were not different from the delta SBP (27.7 ± 2.7) in intact male (IM) mice under the same Ang II conditions determined in a previous study (Rouch, A. el al. FASEB J, 2018, A 904.6). Ang II administration significantly increased water intake and urine flow rate compared to baseline periods in Ang II‐P &amp; Ang II‐T mice with no differences between those two groups, and there was no difference among groups with respect to sodium excretion or sodium balance. Interestingly, renal cortical tissue samples from Ang II‐P mice had higher mRNA expression of ENaC (a,b, &amp; g), NKCC, NCC, and NHE3 compared to those from Ang II‐T mice (FD: 0.7–2.5, p &lt; 0.05). Tissue samples from V‐P mice expressed higher mRNA levels of ENaC (b&amp; g), Na‐K ATPase‐a1, NCC, and NHE2 compared to samples from IM mice (FD: 1.7–2.5, p &lt; 0.05). We conclude that testosterone does not affect the ten‐day Ang II‐induced increase in blood pressure in the CD‐1 mouse. Testosterone reduces mRNA expression of key renal sodium transporters. Physiological consequences of T‐induced changes in mRNA expression remain to be determined.Support or Funding InformationThis project was supported by the National Institute of General Medical Sciences of National Institutes of Health through Grant Number 8P20GM103447.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Research status and development trend of available exhaust energy management for diesel engine at different altitudes

In order to improve the boosting pressure, intake flow rate and matching characteristics of a diesel engine and turbocharging system at varying altitudes, it is very important to utilize and manage available exhaust flow energy. The advanced air management system can effectively utilize exhaust flow energy and improve the intake pressure of the diesel engine at high altitudes. In this paper, the key thermodynamic parameters of air management systems, management of exhaust flow energy and control of air path at different altitudes are reviewed. At last, two aspects containing control strategy, control algorithm of the air management system were put forward.

A Review on Ultrasonic Catalytic Microbubbles Ozonation Processes: Properties, Hydroxyl Radicals Generation Pathway and Potential in Application

Ozone-based advanced oxidant processes (AOPs) have attracted remarkable attention as an alternative and effective approach for mineralization of refractory organics to innocuous substances. Key issues for ozone-based AOPs mainly focused on how to enhance ozone mass transfer and improve the production of hydroxyl radicals. Unfortunately, great efforts have been made, though, the application of ozone-based AOPs still remained in the laboratory scale due to lack of understanding of mechanisms of these hybrid processes. Besides, obtaining the balance of economical-technical feasibility is a great challenge. Ultrasonic catalytic microbubbles ozonation could be considered as a promising method, despite that there are a few studies that addressed this potential technology. Therefore, in this review, summaries about ozone-based microbubbles process, ultrasonic catalytic ozonation process, and ultrasonic catalytic microbubbles ozonation process have been provided in order to give a novel prospective about these hybrid technologies. The main influential parameters, such as initial pH, ozone dosage, intake flow rate, operating temperature, bubble size distributions, ultrasonic frequency, ultrasonic power density, and natural water constituents have also been well discussed. We truly hope that this paper will bring convenience to researchers that are devoted in the field of application of ozone-based AOPs for mineralizing refractory organics in wastewater.

Experimental investigation on thermal management for small container data center

The energy consumptions of data centers are increasing dramatically and cooling systems using for controlling the operating temperature usually consume more than half of these energy. Thus, effective strategies on thermal management in data centers may have benefit on energy savings. In order to improve the power usage effectiveness (PUE) of data centers, the effects of air supply flowrate by computer room air handler (CRAH), intake flowrate of rack cooling fans, air supply grilles and heat load distribution on the cooling performance of a typical small container data center having overhead air supply system are investigated in this paper. The rack cooling index (RCI) and supply heat index (SHI) are incorporated to evaluate the local and average cooling performance of data racks. It is found that the intake flowrate of rack cooling fans plays dominant role, which is suggested to be greater than the air supply flowrate in normal operation. Meanwhile, the volumetric flowrate distribution of grilles is studied. The additional front grille before entering the cold aisle may improve the RCI and SHI of front rack (rack A), in which severe hot-air recirculation may occur in typical operation. Conversely, additional rear grille at the exit of cold aisle has negative effect on cooling performance of the last rack (rack E). Based on the measurement of local temperature distribution, the non-uniform heat load distribution in racks is proposed. Result shows that the RCI can be improved to 64% if more power is placed at lower half part, which is eligible for energy saving. However, the non-uniform heat load distribution shows limited improvement on the rear rack (rack E).

Laboratory Investigation of the Impact of Armor Dike Simple and L-shaped in Upstream and Downstream Intake of the Hydraulic Flow River and Intake Flow Rate

Laboratory Investigation of the Impact of Armor Dike Simple and L-shaped in Upstream and Downstream Intake of the Hydraulic Flow River and Intake Flow Rate

A systematic study of enhanced ozone mass transfer for ultrasonic-assisted PTFE hollow fiber membrane aeration process

The ozone mass transfer efficiency based on deionized water of both the PTFE hollow fiber membrane aeration and ultrasonic-assisted PTFE hollow fiber membrane aeration processes have been studied and described by mass transfer coefficient (KLa). Bubble size distributions were also investigated via an image-technology to analyze mass transfer processes. All the PTFE hollow fiber membranes were hydrophobic and had an asymmetrical structure. Results showed that the maximum value of KLa (0.438 min−1) was obtained at an intake flow rate of 300 L/h with 1# membrane (0.22 µm) in single membrane aeration system. This gas-liquid mass transfer was strongly dependent on pressure. After the introduction of ultrasonic power, the KLa value reached 0.632 min−1 with an ultrasonic power of 1000 W. This enhancement was related to the periodical replacement of local liquid at the interface between the bulk solution and the liquid with high concentration of ozone. The degradation of sulfonated phenolic resin (SMP) confirms that its mineralization was promoted by the enhanced gas-liquid mass transfer of ozone and the generation of OH in the bulk solution.

Effect of Temperature and Intake Flow Rate on the Discharge of Treated Water during Whole Year

Effect of Temperature and Intake Flow Rate on the Discharge of Treated Water during Whole Year

Development of the Long-Term Morphodynamic Model to Determine the Seawater Intake Location

Seawater intake structures are often used at coastal power plant to draw ambient seawater into the cooling system for operation. However, improper selection of water intake location will lead to sediments deposition at the intake structure causing lower intake flow rate, clogging of water filtration devices and reduces the efficiency of the power plant. A 2D process-based model is developed to investigate the morphodynamic behavior of the Kapar coast. The model is developed by coupling the processes of hydrodynamic, waves and sediment transport. The processes are interacted dynamically with bathymetry and lead to the morphological changes. The model is input with the schematisation of seasonal wind-wave conditions and a representative morphological tide. Morphological acceleration technique is used to simulate the long-term morphodynamic changes with acceptable computational times. Sedimentation and erosion patterns are represented by the model and suitable intake location is determined based on the long-term morphodynamic investigation.

Experimental study on the influence of porous foam metal filled in the core flow region on the performance of thermoelectric generators

Semiconductor thermoelectric generator technology is a new type of power generation technology. The use of semiconductor thermoelectric power generation technology for automobile exhaust heat recovery and utilization can effectively improve energy efficiency. In this study, a test system is set up to simulate the automobile exhaust, and the effect of core flow heat-transfer enhancement on the performance of the thermoelectric generator is investigated using thermoelectric module Bi2Te3 to recover the waste heat from automobile exhaust and convert it into electrical energy. The results show that filling foam metal can significantly improve the performance of the generator. The convective heat-transfer coefficient of the channel increases by four times, and the output power of the thermoelectric generator is doubled when the intake flow rate is 120m3/h, the inlet temperature is 300°C, the pore density of the foam metal is 20 pores per inch, and the filling rate of the foam metal is 75%. In addition, the improvement in the performance of the generator is different under different intake air flows, different foam-metal filling rates, and different pore densities.

A Conjugate Natural Convection Model for Large Scale Seasonal Thermal Energy Storage Units: Application in Mine Ventilation

Ventilation plays an important role in energy demands of mining industry. Using the immense volume of waste rock as thermal energy storage mass to shave seasonal air temperature oscillations is a genuine and practical solution to save on ventilation energy demands. The extensive size and considerable temperature gradients exhibited in such systems point to the importance of buoyancy-driven natural convection heat transfer mechanism. The present study investigates the effect of natural convection and identifies the order of significance of various heat transfer mechanisms. A Conjugate heat transfer and fluid flow model is proposed which includes both the porous rock mass placed in the rock-pit and the air positioned above it. The results of the model are compared and validated against the existing Non-Conjugate models. Using this novel model, significance of forced convection, driven by ventilation fan, and natural convection, driven by buoyancy, are compared. The model is also used to study how design parameters, such as position of intake air trenches and flow rate of fresh air, will affect energy savings.