Streaming Rate Research Articles

Investigation of entropy generation in nanofluid’s axisymmetric stagnation flow over a cylinder with constant wall temperature and uniform surface suction-blowing

Dimensionless temperature, Nusselt number and entropy generation in stagnation flow of incompressible nanofluid over an infinite cylinder accompanying uniform suction and blow in steady state have been investigated in this study. Free stream has been steady as well with the initial stream rate of k¯. Dimensional analysis and similarity solution of Navier-stokes and energy equations have been presented. These equations are simplified implementing appropriate transformations introduced in this research. The similarity equations are solved where the cylinder’s wall is under constant Temperature. All these solutions are acceptable for Reynolds numbers Re=k¯a2/2υf of 0.1–1000, various dimensionless surface diffusion S=Uo/k¯a and specific volume fractions of nano particles where a is the cylinder radius and υf is the kinematic viscosity of the base-fluid. The results show that for all Reynolds numbers, diffusion depth of radial and axial components of velocity field and wall shear stress increases as a result of decline in nano particles volume fraction and growth in surface diffusion. Moreover, increase in nano particles volume fraction and surface suction raises heat transfer coefficient and Nusselt number. Also the largest amount of entropy generated is calculated.

Design and analysis of an intensified column with side reactor configuration for ethylene glycol production from ethylene oxide

The side reactor concept (SRC), comprising a non-reactive column coupled with side reactors, is proposed for the synthesis of ethylene glycol (EG) by ethylene oxide (EO) hydration. Parallel isothermal continuous stirred tank reactors are employed and the combinations of the reactors and the column are cautiously examined. A preliminary analysis of the operating conditions for the reaction and separation and the detailed SRC configurations (such as the side stream rate, side stream location) are performed to generate the suggested values or ranges for their further optimization. The decisive variables are subsequently optimized by a sequential design procedure. The significant effects of the key decision variables on the trade-off between the reaction cost and the separation cost are well investigated. The reactor–separation unit, configured with a total liquid withdrawn and recycled back to the column stage below, demonstrates better system performance. Furthermore, the reaction at elevated temperature (150 °C) conductive for reaction and the separation occurring at the distillation temperature range of 106∼204 °C (124 kPa) gives out improved economic performance. Flexibility in the operating conditions in SRC makes it a competitive alternative to the RD process for EG production.

Fluvial Erosion Rate of Cohesive Streambanks Is Directly Related to the Difference in Soil and Water Temperatures

Despite decades of research in the field of cohesive soil scour, a major challenge in water resource engineering is an understanding of the fundamental processes governing the erosion of cohesive streambank soils. Given that cohesive soil erodibility is affected by many factors simultaneously, it is necessary to study these factors independently to obtain insights into the erosion process. Three natural soils with different mineralogies were chosen for this study: montmorillonite‐dominated fat clay, vermiculite‐dominated lean clay, and kaolinite‐ and illite‐dominated silty sand. The soils were remolded at maximum dry densities and optimum moisture contents and subjected to 15‐min erosion tests in a laboratory flume. Erosion tests were performed at water temperatures of 15 and 25°C and corresponding soil temperatures of 0, 15, and 25°C, and 15, 25, and 40°C. Test results show that, irrespective of soil type, erosion rate increased with an increase in water temperature but decreased with an increase in soil temperature. When soil and water temperatures were equal, there was no significant change in erosion rate (α = 0.05). Further analyses showed that, irrespective of soil type, erosion rate was a function of the difference in soil and water temperatures and not either temperature alone, indicating that the important thermal factor in the erosion process was the difference in soil and water temperatures. These results show the importance of accounting for soil and water temperatures in erosion studies and suggest that the use of stormwater control measures to control runoff temperatures may be necessary to combat streambank degradation resulting from urbanization.Core Ideas Fluvial erosion of cohesive streambanks is affected by soil and water temperatures. Soil and water temperatures have a coactive effect on cohesive streambank erosion. Increases in stream temperature increase fluvial erosion rates of cohesive banks. Increased streambank temperature reduces fluvial erosion rates of cohesive soils. Urban stormwater runoff temperatures should be reduced to maintain channel stability.

Gas exchange in streams and rivers

AbstractGas exchange across the air–water boundary of streams and rivers is a globally large biogeochemical flux. Gas exchange depends on the solubility of the gas of interest, the gas concentrations of the air and water, and the gas exchange velocity (k), usually normalized to a Schmidt number of 600, referred to as k600. Gas exchange velocity is of intense research interest because it is problematic to estimate, is highly spatially variable, and has high prediction error. Theory dictates that molecular diffusivity and turbulence drives variation in k600 in flowing waters. We measure k600 via several methods from direct measures, gas tracer experiments, to modeling of diel changes in dissolved gas concentrations. Many estimates of k600 show that surface turbulence explains variation in k600 leading to predictive models based upon geomorphic and hydraulic variables. These variables include stream channel slope and stream flow velocity, the product of which, is proportional to the energy dissipation rate in streams and rivers. These empirical models provide understanding of the controls on k600, yet high residual variation in k600 show that these simple models are insufficient for predicting individual locations. The most appropriate method to estimate gas exchange depends on the scientific question along with the characteristics of the study sites. We provide a decision tree for selecting the best method to estimate k600 for individual river reaches to scaling to river networks.This article is categorized under: Water and Life > Nature of Freshwater Ecosystems Science of Water > Water Quality Water and Life > Methods

Measurement of transient evaporation of an ethanol droplet stream with phase rainbow refractometry and high-speed microscopic shadowgraphy

Quantifying the evaporation rate of droplets is of great importance in many applications and this is especially true if the evaporation occurs in a rapidly changing environment, such that models describing evaporation under steady state conditions are no longer valid. To achieve such information from experiments, the phase rainbow refractometry (PRR) technique has recently be shown to be capable of simultaneously measuring temperature, size, and size variation at the nanometer scale, quantities essential for quantifying transient evaporation rates. The present study examines the use of the PRR technique to characterize the evaporation of monodispersed droplets in a droplet stream injected into ambient air. This is combined with high-speed microscopic shadowgraphy, yielding as measured quantities droplet diameter, diameter change, temperature evolution, velocity and computed transient evaporation rate of the droplet stream. The accuracy and resolution of the measurements are evaluated by comparison with theoretical values and values measured with alternative means. Furthermore, the results are used to investigate how the evaporation rate is modified by interaction among droplets in the droplet stream and how these rates differ from evaporation rates predicted for isolated droplets, using the well proven Abramzon and Sirignano model. Finally, the evaporation rate, including the influence of droplet interaction, is shown to be in line with correlations suggested by Virepinte; refinement to this correlation is proposed.

Optimal Stream Gauge Network Design Using Entropy Theory and Importance of Stream Gauge Stations

Stream gauge stations are facilities for measuring stream water levels and flow rates, and their main purpose is to produce the data required to analyze hydrological phenomena. However, there are no specific criteria for selecting the locations and installation densities of stream gauge stations, which results in numerous problems, including regional imbalances and overlapping. To address these issues, a stream gauge network was constructed in this study considering both the transinformation of entropy (objective function 1) and the importance of each stream gauge station (objective function 2). To account for both factors, the optimal combinations that satisfied the two objective functions were determined using the Euclidean distance. Based on the rainfall runoff analysis results, unit hydrographs reflecting stream connectivity were derived and applied to entropy theory. The importance of each stream gauge station was calculated considering its purposes, such as flood control, water use, and environment. When this method was applied to the Namgang Dam Basin, it was found out that eight out of 12 stream gauge stations were required. The combination of the selected stations reflected both the transinformation of entropy and the importance of each station.

A DHT-Supported Piece Driven Overlay for P2P Live Gushing

Peer-to-peer live streaming technologies allow a constricted source of data transmission to transmit a video that encourages a significant amount of customers. The primary objective of live gushing is to convey stream information to all customers previously their playback due date. Outline effectiveness is basically described by the spilling rate that can be managed, and by the postpone it takes for information to achieve customers from the source. Furthermore, a plan with high connection usage can accomplish high stream rates, supporting amazing video. As of recently, just tree-based plans have been appeared to accomplish near ideal rates, all items regarded, circumstances, leaving the investigation open as to the viable efficacy of completely unstructured methodologies based on job.We answer that inquiry by demonstrating that a painstakingly composed work based framework can accomplish near ideal stream rates In particular, in the context of a work-based count called DP / LU, we are executing and surveying a structure. Instead of tree-based diagrams, DP / LU utilizes an unstructured overlay that is less demanding to produce and extremely impenetrable to mix. Moreover, we recognize a few outline advancements which help enhance the rate and defer execution of work based frameworks. Our experiment evaluation shows that in a static scenario, our sketch achieves 95% of the most severe achievable flow speed and 90% under elevated agitate. This displays work-based outlines are an amazing choice for live spilling distributed versatile and powerful top notch. Live video spilling administrations are spreading rapidly finished the Internet. To tell the truth, many frameworks use basic gushing conventions that underuse uplinks from customers, squandering accessible transmission capacity. This problem will turn out to be more authentic as customers will demand top notch entertainment in the near future, increasing the necessary stream bitrates. This prompts the associated investigation: are tree-based plans going to exchange working schedules oriented on top-notch live video gushing? We trust that the appropriate response is no. To help this, we play out an examination which demonstrates that a precisely planned work based framework can accomplish close ideal rates and low dissemination delays.

Real-time Dash Streaming Architecture for Internet of Things Using FBMRWP Model for Medical Videos.

The proposed method uses random adjustments in the online video quality based on the bandwidth allocated over Dynamic Adaptive Streaming over HTTP (DASH) streaming service. The main objective is to improve the video quality from DASH-HTTP servers with variable bandwidth. Here, the system is adjusted dynamically for providing best video quality services based on the requirement of the user. In order to achieve such objective, the DASH service is assigned with three modules. Initially, the quality is adjusted dynamically using Fractional Brownian Motion and Random Waypoint Mobility (FBM-RWP) model. This initial model schedules the packets in sub-streams based on the priority as per the requirement of the user. The final model uses the Proportional Integral Derivative (PID) quality control algorithm for the past and future prediction of quality based on bandwidth allocation. This feedback of quality is used by the FBM-RWP model to prioritize the packets in the sub-streams. The entire process works by matching the bit rate of video streaming with the user required quality. Resuslts: The technique concentrates mostly on medical videos for improving the live video streaming in case of medical emergencies. The performance of the proposed method is compared with the conventional DASH services. The results proved that the proposed method performs better in terms of reduced error and improved throughput.

Comparison of MongoDB and Cassandra Databases for Spectrum Monitoring As-a-Service

Due to the growing number of devices accessing the Internet through wireless networks, the radio spectrum has become a highly contended resource. The availability of low cost radio spectrum monitoring sensors enables a geographically distributed, real-time observation of the spectrum to spot inefficiencies and to develop new strategies for its utilization. The potentially large number of sensors to be deployed and the intrinsic nature of data make this task a Big Data problem. In this work we design, implement, and validate a hardware and software architecture for wideband radio spectrum monitoring inspired to the Lambda architecture. This system offers Spectrum Sensing as a Service to let end users easily access and process radio spectrum data. To minimize the latency of services offered by the platform, we fine tune the data processing chain. From the analysis of sensor data characteristics, we design the data models for MongoDB and Cassandra, two popular NoSQL databases. A MapReduce job for spectrum visualization has been developed to show the potential of our approach and to identify the challenges in processing spectrum sensor data. We experimentally evaluate and compare the performance of the two databases in terms of application processing time for different types of queries applied on data streams with heterogeneous generation rate. Our experiments show that Cassandra outperforms MongoDB in most cases, with some exceptions depending on data stream rate.

Process engineering strategy for cultivation of high density microalgal biomass with improved productivity as a feedstock for production of bio-crude oil via hydrothermal liquefaction

A process engineering strategy was developed for cultivation of high density biomass of Chlorella sp. FC2 with improved productivity under photoautotrophic condition. The process engineering strategy involved a combinatorial approach of: (i) optimization of CO2 concentration in the inlet gas stream & aeration rate; (ii) growth kinetic driven feeding recipe for limiting nutrients; and (iii) dynamic increase in light intensity. The strategy was tested by growing the cells on laboratory grade BG11 medium. With an attempt to reduce the cultivation cost, the growth performance of the organism was then evaluated on commercial grade BG11 medium. Finally, hydrothermal liquefaction was carried out for direct conversion of microalgal slurry into bio-crude oil. Cultivation on laboratory grade BG11 medium resulted in biomass titer and overall productivity of 8.41 g L−1 and 575.9 mg L−1 day−1 respectively. Significant improvement in biomass titer (13.23 g L−1) and overall productivity (731.6 mg L−1 day−1) was observed when grown on commercial grade BG11 medium. Higher fraction of hydrocarbon in the bio-crude oil depicted better oil quality. Thermal gravimetric analysis revealed that maximum distillate fraction lies within the boiling point range of 200–300 °C which is suitable for conversion into diesel oil, jet fuel, and fuel for stoves.

Joint Rate and Power Optimization for Multimedia Streaming in Wireless Fading Channels via Parametric Policy Gradient

In this paper, we consider the two-timescale queueaware resource control for wireless video streaming applications. By applying a singular perturbation approach, we study a twotimescale joint optimization of transmission power and streaming rate control for real-time video streaming. The timescale parameter e is introduced to separate the state variables into slow and fast varying groups, and the power control is adaptive to both the channel state information and the playback queue state information (QSI) at the fast timescale, while the streaming rate representing the video quality is only adaptive to the QSI at the slow timescale. We first derive the averaged system by taking the perturbation parameter e → 0, and the limiting problem is a firm approximation for the formal problem with small e. Based on the averaged system, we derive the Hamilton-Jacobi-Bellman equation and show that the optimal control policy has a structural property which can further help us to simplify the problem. We use the parametric policy reinforcement learning algorithm to obtain the optimal parameterized policy, and show the algorithm convergence result. Finally, the proposed scheme's performance is compared with various baselines through simulations and it is shown that significant gain can be achieved.

Plant phylogenetic history explains in‐stream decomposition at a global scale

Abstract Evolutionary history and adaptation to climate shape plant traits. Some include leaf traits that influence litter quality. Thus, evolutionary history should affect litter decomposition, a crucial ecosystem process. In addition, litter decomposition is directly influenced by climate. We consequently expect plant phylogeny, adaptation and climate to jointly influence litter decomposition. These effects and their interactions have yet to be untangled at a global scale. Here we present an analysis of variation in litter decomposition rates in rivers and streams across 285 published studies for 239 species (from ferns to angiosperms) distributed at 494 locations world‐wide. We estimated the relative contributions of climatic conditions and phylogenetic heritage on litter decomposition rates, partitioning phylogenetic from climatic effects at the site and species levels using phylogenetic eigenvector analysis and phylogenetic linear mixed models. In addition, we modelled transitions in decomposition rates under a suite of multiple adaptive‐regime Ornstein–Uhlenbeck models to test the hypothesis that natural selection has shaped clade‐level litter decomposition rates. Leaf litter decomposition rate exhibited a significant phylogenetic signal. Modelling decomposition rate as a function of location, climatic niche and phylogeny consistently recovered phylogeny alone as one of the top models in species‐level analyses. Since many previous studies have focused on the same species across many locations, we also conducted analyses at the species × site level. Both phylogenetic and climatic factors were favoured in models of this analysis, but the single most important predictor for angiosperms and for all taxa analysed together was phylogeny alone. Synthesis. For plant species distributed globally at nearly 500 locations we found that plant phylogenetic history is a critically important predictor of litter decomposition rate in rivers and streams, explaining more of the variance in decomposition than site or climatic regime. Thus, our study demonstrates the influence of evolutionary history on suites of plant traits that shape a key ecosystem process.

Intrusion detection system in gas-pipeline industry using machine learning

In this paper, we study about the plausibility of building up a total intrusion identification framework for gas pipeline industry utilized in present day man-made AI based frameworks to tell a gas controller of unexpected changes in pipeline working qualities, for example, weight, time interim, delta pipeline PSI and stream rate. This examination assesses the possibility for utilizing AI example of cautions strategies utilizing three able AI calculations, for example, Decision tree, K-Nearest Neighbor and Neural Network to recognize breaks in gas frameworks, like the SCADA rate of progress blend philosophy utilized by the risky fluids pipeline industry. The highlights were extricated from the dataset by evacuating the repetitive information too cleaning the information. The significant commitment to this work is by utilizing choice tree in three distinct degrees for example randomized, advanced and timberland just as utilizing the neural system with 3 layers, 20 units for each concealed layer, 20 preparing rounds and with 2 layers, 50 preparing rounds as appeared in down to earth some portion of this work executed in Matlab R2019a to recognize and foresee the potential assault in the gas pipeline industry. The idea of AI examination considered here shows guarantee, in light of the aftereffects of gas pipeline burst checking under the conditions tried. It can possibly be formed into a compelling crack checking technique, yet additionally testing under genuine world, complex-framework setups, in participation with appropriate AI demonstrating specialists, is expected to all the more likely comprehend the genuine practicality of this adjustment mechanized innovation. Since gases and fluids display diverse physical practices under changing weight and stream conditions an immediate relationship between's the viability in gas versus fluids frameworks can't be accurately expected that why AI would give the answer for variety in Pipeline PSI and complete delta pipeline PSI. For example, by-passing and back-feeding, and various other framework explicit conditions requiring redid arrangements utilizing AI.

Automated water Distribution System in Metro’s using IOT

In urban regions, the water supply to home and business foundations are given at a settled stream rate. There are occurrences of overabundance water drawn by specific clients/clients for example water will be discharged informally, which is considered as water burglary. In this undertaking, it is proposed to build up an inserted based remote water observing and robbery counteractive action framework by taking the information of water supply at the purchaser/client end. The general goal of a conveyance framework is to convey healthy water to the buyer at specific territory and the inadequate amount and accomplish progression and most extreme inclusion at moderate expense. To accomplish the target the association needs to advance working strategies to guarantee that the framework can be worked palatably, work proficiently and ceaselessly beyond what many would consider possible at most reduced expense. Here we are utilizing PIC16F877A as our controller and furthermore, a couple of sensors are masterminded to distinguish the nearness of water in that specific pipeline. IR sensors are utilized to distinguish the water stream. Water ought to be discharged according to the directions by authority's for example for instance exchange long stretches of supply are given and just amid explicit timeframe however not day by day.

Experimental studies on inclined PV panel solar still with cover cooling and PCM

This work presents the experimental studies on the effect of mass stream rate of water (mf), phase change material and cover cooling of an inclined solar panel basin solar still (ISPBSS). Experimental results revealed that cooling the entire surface of the glass cover of ISPBSS with fully opened flow of water produced the maximum distilled water. On varying mf, the glass temperature is higher during the minimum mf. With increased mf from 7.35 to 13.32 and from 7.35 to 17.72 kg h−1, the glass temperature is almost equivalent to the ambient temperature with fully opened flow cover cooling technique. The reduced glass temperature enhanced the rate of condensation. Similarly, the hourly instant efficiency of the ISPBSS with fully opened cover cooling is higher as compared with the similar ISPBSS without and with partially cover cooling condition. The highest hourly instantaneous efficiency of ISPBSS with partially and fully opened cover cooling is found as 85% and 88%, respectively.

Fast, facile and scalable fabrication of novel microporous silicalite-1/PDMS mixed matrix membranes for efficient ethanol separation by pervaporation

Ethanol pervaporation during its fermentative production alleviates product inhibition and hence enhances bioethanol production as a source of renewable energy. In this work, a novel microporous silicalite-1/PDMS mixed matrix membrane was fabricated by spraying as a facile, fast and low-cost method on a flat ceramic membrane. The effect of PDMS (0.05–0.15 g/ml), silica (0–0.06 g/ml) and curing temperature (80–150 °C) on the separation factor and permeation flux of the membranes was investigated using Box-Behnken design for separation 5 wt% ethanol/water solution at 30 °C which circulated at 400 (ml/min). Membranes were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and contact angle (CA). PDMS concentration acted as an influential factor. Higher curing temperatures led to separation factors less than one due to the higher density of the PDMS matrix. While lower temperatures caused low density, which decreased separation factors. Consequently, pervaporation performance improvement according to the hydrophobicity is possible as far as negative effects on the density of the polymer matrix can be controlled. Additionally, effects of temperature (30–70 °C), concentration (5–10 wt%), and flow rate (400–1000 ml/min) of the feed stream on the optimal membrane performances were examined. The best performances of permeation flux of 3.64 (kg/m2·h) and separation factor of 17.24 corresponded to the membrane (0.08 (g/ml) of PDMS, 0.06 (g/ml) of silica and curing temperature of 109.5 °C) with CA of 142° for separating 5 wt% solution at 60 °C and 400 ml/min. Eventually, this novel membrane can enhance bioethanol production and make it more affordable.

Air-gap diffusion distillation: Theory and experiment

A novel Air-Gap Diffusion Distillation (AGDD) technology operated at normal atmospheric pressure was proposed in this paper. In this plant, cold and hot streams flow counter-currently and the strong hydrophilic porous medium is employed as the hot stream channel to control its flow. The operation characteristics of AGDD were investigated and analyzed theoretically and experimentally. Influences of structure and operation parameters on the performances were discussed deeply. The results showed the water productive flux and Gained Output Ratio (GOR) for the AGDD with one air-gap combination were 0.7244 kg·m−2·h−1 and 1.16 respectively when the thickness and height of air-gap, inlet temperatures of cold and hot streams, mass flow rate of cold stream were 5 mm, 0.9 m, 25 °C, 65 °C and 4 kg·h−1 respectively. When the air-gap height was enlarged to 1.8 m and the mass flow rate of cold stream reduced to 2 kg·h−1, the water productive flux and GOR were 0.5255 kg·m−2·h−1 and 5.01 respectively. The results also indicated that the thermal resistance of heat transfer in the AGDD mainly sourced from the air-gap. The variations of structure or operation parameters did not influence on the desalination rate of AGDD which was higher than 99.8% during experiments.

Effects of Multi-stack Ball Grid Array on Multi-stack Printed Circuit Board

In the customary underfill (CUF) epitome process, there are couple of downsides experienced for instance, extended filling time, divided filling and voids improvement. Test and FVM reenactments have been directed to examine CUF dispensing systems for different types of ball grid array (BGA) tendencies out of a solitary layered PCB. In this task, the principle point is to enhance the stream of under filling mold crosswise over multi-stacks BGA. Package on Package (PoP), a strategy for coordinated circuit bundling, is utilized to consolidate BGA bundles vertically to permit higher segment thickness in devices. The L-type liquid stream in multi-stack BGA with edge introduction is contemplated and parameters of CUP exemplification, for example, void development and filling time were examined. The results demonstrated that the BGA sizes with the little weld balls put at the base layer, trailed by the medium size bind balls in the center stack and the biggest patch balls at the top layer has appeared to enhance the stream rate of the encapsulant ideally. Other arrangement in which the medium size solders placed are at the base layer, small solders at the center layer and largest solders on top of it, requires longest total filling time. The result also shows that the racing effect is present at central region and at the side of the layer. Because of the perimeter orientation design, the void formation is minimal and the race effect is not affecting much according experimental and computational result. This investigation additionally uncovers the capability of air gaps in improving velocity and pressure distribution near inlet and outlet to achieve faster total filling time at all layers of the BGA.

Trace Element Mass Flow Rates from U.S. Coal Fired Power Plants.

Trace elements (TEs) exit coal-fired power plants (CFPPs) via solid, liquid, and gaseous waste streams. Estimating the TE concentrations of these waste streams is essential to selecting pollution controls and estimating emission reduction benefits. This work introduces a generalizable mass balance model for estimating TE mass flow rates in CFPP waste streams and evaluates model accuracy for the U.S. coal fleet given current data constraints. We stochastically estimate, using a bootstrapping approach, the 2015 plant-level mass flow rates of Hg, Se, As, and Cl to solid, liquid, and gas phase waste streams by combining publicly available data for combusted coal TE concentrations with estimates of TE partitioning within installed air pollution control processes. When compared with measured and reported data on TE mass flow rates, this model generally overestimates masses by 30-50%, with larger errors for Hg. The partitioning estimates are consistent for Se, As, and Cl removal from flue gas, but tend to underestimate Hg removal. While our model is suitable for first-order estimates of TE mass flows, future work to improve model performance should focus on collecting and using new data on TE concentrations in the coal blend, where data quality is the weakest.

A quasi-three-dimensional thermal model for multi-stream plate fin heat exchangers

In this study, a novel pseudo-three-dimensional model is developed to find out both fluid and solid temperature distributions in multi-stream plate fin heat exchangers. In this simulation algorithm, heat exchangers can be in either parallel flow or cross flow configuration. The model considerations include: heat leakage of cap plates and side plates, conduction throughout the solid matrix of the heat exchanger, variable physical properties, and inlet mass flow rate maldistribution. Using the computational code, the effects of different factors such as: the number of layers, mass flow variation, inlet mass flow rate maldistribution, and stacking pattern on the thermal performance of the heat exchanger have been investigated. The results of this investigation show that when the number of layers for each stream is small, a linear nonuniformity in the mass flow rate of a hot stream has a more destructive effect on the thermal performance than that in a cold stream. Moreover, the heat transfer rate of the heat exchanger is more sensitive to mass flow deviation of cold streams than that of hot streams. In the present research, when the number of unit cells are higher than 15, periodic boundary conditions can be applied to reduce the computational cost.