Exhaust Manifold Research Articles

Analysis the Influence of Pressure Distribution on Exhaust Manifold Using FEM

Abstract: In this paper the 3D model of the exhaust manifold was realized using Autodesk Inventor Professional 2024 and finite element analysis was performed, in order to determine the state of stress and deformation, by applying restrictions and loads conditions. The materials chosen, for exhaust manifold, was in accordance with the specialized literature. The materials taken for static analysis was Stainless Steel 440C and Iron Gray Cast. Following the comparative study for the two models, it can be specified that the importance of the material for the construction of the exhaust manifold depends on the mass properties and their design

Reactive Condensation of Cr Vapor on Aluminosilicates Containing Alkaline Oxides

The research presented herein is part of a larger project delving into the mechanisms and pathways for reactive condensation of Chromium (Cr) vapors in high-temperature (>500o C) environments. The overall goal of this research project is to improve fundamental understanding of reactive condensation pathways for chromium (Cr) vapors generated in high-temperature systems such as exhaust manifolds, steam turbines, boilers, or solid oxide fuel cells (SOFCs). Reactive evaporation of Cr from stainless steels commonly used in these systems is well-documented; however, the interactions between volatilized Cr species and surrounding interfaces during complex and dynamic system exposures is poorly understood. Understanding the interactions between volatilized Cr species and downstream components during operation is critical for improving system performance, environmental health, and safety as some condensed Cr forms toxic hexavalent Cr(VI) species. The focus of this study is on the effects of alkaline oxides present within the substrate material on reactive condensation mechanisms of Cr vapors. Studying the reaction mechanisms between Cr vapors and ceramic surfaces has direct application to SOFCs as these materials are widely used in the field. For example, alumina-silica glass-ceramics are used as sealants in SOFCs. These materials belong to the SiO2–Al2O3 system and contain different compositions of oxides including CaO, Na2O, MgO, K2O, B2O3, Y2O3, and BaO. Another sealing material used in SOFCs is mica, a class of silicate minerals that forms into distinct layers. Two types of mica commonly used in SOFC applications are muscovite (potassium aluminum silicate hydroxide fluoride, KAl2(AlSi3O10)(F,OH)2), and phlogopite (potassium magnesium aluminum silicate hydroxide, KMg3(AlSi3O10)(OH)2). The specific research objective is to explore the effects of alkaline oxide additives in aluminosilicates on Cr collection and speciation. To accomplish this objective, an experimental platform was designed to assess interactions between samples of high-temperature steel alloys or Cr oxide (Cr2O3) powder with ceramic insulating materials. The chemical composition of the insulating materials used in this study range from pure silica (SiO2) and alumina (Al2O3) to combinations thereof with and without inclusions of alkaline earth metals (e.g., Ca, Mg). Preliminary results show three- to four-fold increases in Cr(VI) formation on silica fibers with weight percentages of ~30 and ~40 percent alkaline oxides (CaO and MgO), respectively, after exposure to volatile Cr species, relative to low-alkaline silica. Figure 1 presents an overview of the experimental concept, Cr(VI) test kit, and preliminary results for dependency on alkaline oxide content. Figure 1

Increasing the wear resistance of the ICE’s valves with the laser cladding method

BACKGROUND: There is plenty of factors leading to failure and expensive repair of piston engines at their operation. One of the widespread factors capable of affecting the engine operation is combustion chamber sealing failure. During the engine operation, gases combusting in a chamber bring pressure on working surfaces of a valve and a valve seat. If these surfaces do not ensure sealing, exhaust gases begin to leak in the exhaust manifold untimely, in some cases in the intake manifold as well. In addition, filling of cylinders with inlet charge worsens. In majority of cases, combustion chamber sealing failure caused by defect formation at working surfaces of the valve — valve seat coupling. In order to avoid combustion chamber sealing failures and other issues of operation of piston engines, it is necessary to minimize working surfaces wearing by means of wear-resistant coating. AIMS: Wear- and corrosion-resistant coating of valve’s working surface to increase service life. METHODS: The factors affecting the reliability of the valve — valve seat coupling were defined by means of literary sources analysis. Laser cladding at the valve’s chamfer was conducted with the laser robotized facility based on ytterbium fiber laser. Quality of the coated surface at the valve’s working chamfer was defined by means of metallographic study and liquid penetrant test. RESULTS: After laser cladding of the PR-08Kh17N8S6G powder material at the valve’s working chamfer, the uniform coated surface with microhardness of 435–485 HV (44–48 HRC) was obtained. CONCLUSIONS: The study results may be used for development and implementation of new kinds of wear-resistant surfaces that make it possible to increase the service life and to repair worn-down surfaces of components.

A study on the significance of exhaust manifold’s bending angle to the brake torque of 115cc SI engine

The exhaust manifold is a crucial component of the exhaust system in any SI engine, responsible for efficiently expelling combustion products. However, when the exhaust manifold’s design is suboptimal, it leads to negative consequences for the engine’s performance due to the presence of backpressure. Backpressure refers to the difference between maximum exhaust pressure and atmospheric pressure. An increase in backpressure decreases the overall performance and fuel efficiency of an SI engine. This study aimed to investigate the bending angle characteristics of the exhaust manifold and the brake torque of the 115cc SI engine using 1D engine analysis. The relationship between the exhaust manifold’s bending angle characteristics and the brake torque was analysed using Analysis of Variance (ANOVA) with a p-value of less than 0.05, while the validation with experimental data showed a maximum error of 6.62. In the previous research, it was noted that a lower bending angle leads to better performance. However, the current results indicate that out of the three bending angles considered, having one of them yields the most substantial enhancement in brake torque. The optimized bending angle configuration obtained from the analysis increased the mean brake torque by 0.011 Nm (0.14%). Consequently, this study enhances the average brake torque through the optimal bending angle characteristics of the exhaust manifold. The study’s objective aligns with Sustainable Development Goal (SDG) 9: Industry, Innovation, and Infrastructure, as the improved performance achieved through an optimal exhaust manifold design configuration is expected to promote domestic technology development.

An Analysis on the Thermal Flow Characteristics of the Car Exhaust Manifold Geometry

The exhaust manifold is connected to the engine cylinder block and concentrates the exhaust from each cylinder into the exhaust manifold with divergent piping. Research on how the stability and efficiency of the exhaust manifold affects the aftertreatment system of an automobile is actively conducted. Therefore, this article studies to derive the most suitable model for the design of the exhaust manifold of an automobile by analyzing and comparing its pressure distribution, flow distribution, and temperature distribution according to the different shapes of the exhaust manifold. The thermal characteristics were studied and analyzed using FLUENT in ANSYS 2019R3. The results of the analysis are as follows, based on the results of the comparative analysis of the pressure distribution, case 1 shows a low-pressure difference of 200 Pa. In the results of the analysis of the flow rate, the flow rate fluctuations are confirmed in cases 3, 2 and 1 in sequence. Furthermore, when the temperature distribution was analyzed comparatively, it was found that the shape of the car exhaust manifold did not have an effect on the temperature. Therefore, as a result of these findings, the Case 1 model was inferred to be the most suitable model for the design of the exhaust manifold shape of the automobile.

Failure analysis of a natural gas engine exhaust manifold

The causes of exhaust manifold failure of a natural gas engine were investigated in terms of both the material and structure. First, the material analysis, including chemical component and mechanical properties, were carried out by material tests and data analysis. Then, the temperature and thermal stress of exhaust manifold under thermal shocks were calculated by finite element method. Finally, the initiation and propagation of cracks and improvement design of exhaust manifold were discussed. The results showed that the highest temperature of exhaust manifold was 715 °C and the maximum thermal stress was 455 MPa. The yield deformation occurred during thermal shocks. And the sharp structural change at the critical induced thermal stress area raised the possibility of shrinkage pores. Therefore, the low cycle fatigue failure was the main reason of the exhaust manifold failure. And structure optimization and alternation of material properties were two most basic and effective technological approaches.

Unsteady gasdynamic modeling of double-entry turbine integrated with engine exhaust manifolds

Pulsating turbocharging system with a dual-entry turbine is always applied for the utilization of pulsating energy and improvement of low-speed torque for the internal combustion engine. With the enhancement of pulsating energy via the pulsating turbocharging system and dual-entry turbine, the interaction between exhaust manifolds and dual-entry turbine cannot be disregarded by either side when confronted by pulsating inflows. This paper proposes a gasdynamic model of double-entry turbine coupling with exhaust manifolds to examine the interaction effect between turbine and exhaust manifolds. This gasdynamic model can predict the propagation of pressure and mass flow rate from exhaust manifolds to the double-entry turbine as well as transient turbine performance. Predictions of this gasdynamic model are validated against detailed 3-D simulation and show good consistency with 3-D results. The performance and energy distribution of the double-entry turbine coupled to exhaust manifolds under various pulsating conditions are thoroughly discussed via this reduced-order model. Results show that with increasing frequency or amplitude of pulsating inflows imposed on inlets of the exhaust manifolds, the performance of the entire system deviates from the quasi-steady hypothesis, particularly the swallowing capacity. This phenomenon indicates that the matched operating point between the turbine and engine deviates from the quasi-steady conditions. In addition, exhaust manifolds geometries have a notable impact on turbine performance and energy distributions in exhaust systems. It is found that with an increase in the volume or length of the exhaust manifolds, the pulse at the turbine inlet is amplified, and available energy at the turbine inlet is increased, even though the inlet conditions of exhaust manifolds remain unchanged. This study may provide a guiding effect for the optimization of the turbo-engine matching process and the development of high-performance turbocharged engines.

Influence of exhaust manifold modification on engine power

The article deals with the subject of the impact of an exhaust system on the power of the internal combustion engine. In particular the article shows the possibility of increasing a power of the gasoline drive unit, interfering only with an exhaust system. The purpose of the tests carried out is to compare the results of measurements from the chassis dynamometer before and after the modification, and additionally to perform simulations for the key parts of the system in terms of shaping the power and torque curves. The analysis includes a simulation model of the exhaust gas flow through the serial manifold and also the sport manifold, especially the pressure distribution and the course of the velocity vectors at the characteristic points of the element. Before obtaining the final results of power measurements on the sport units, the roughness of the steel from which the collectors were made was also measured. The final stage is the measurement of power on the new exhaust system. The obtained results of power measurements and simulations were presented in the form of a summary, which focused on the impact of individual fluid mechanics phenomena on the formation of power and torque curves and detailing the advantage of the new exhaust system in comparison with factory system in terms of increasing the performance of the tested vehicle.

Experimental and theoretical analysis of exhaust manifold by uncoated and coated ceramics (Al2O3, TiO2 and ZrO2)

This research work focuses on the experimental and theoretical analysis of the exhaust manifold with novel ceramic coatings (TiO2 Coatings; ZrO2 coatings; and Al2O3 coatings) and these coatings were applied on the manifold by the plasma arc technique with a temperature range of 14,000 οC and micron coatings ranging from 350 to 400μ. The implementation of these coatings over the exhaust manifold gives enormous benefits such as improvised endurance strength, higher heat dissipation, and flexible directional heat flux compared to uncoated materials. From the numerical analysis, it is found that the ceramic coatings give lower thermal residual stresses compared to the uncoated materials. Among the three coatings, Al2O3 coatings give optimal performance in terms of heat dissipation, heat flux, and directional heat flux and also lower thermal residual stresses. From the overall analysis; it is also clear that the implementation of ceramic coatings on the exhaust manifold gives enormous advantages in terms of corrosion resistance and lesser maintenance as compared to uncoated materials.

Hydrocarbon and particulate matter evolution in the exhaust manifold of a spark-ignited engine under cold-start operation

Cold-start, as defined by the time between first engine crank and three-way catalyst light-off, is responsible for a large percentage of NOx, unburned hydrocarbon, and particulate matter (PM) emissions in light-duty engines. Minimizing emissions during cold-start is a trade-off between achieving faster three-way catalyst light-off, and engine out emissions during that period. In this study, various exhaust gas and PM species were measured at three locations in the exhaust manifold using advanced hydrocarbon and PM speciation methods in addition to standard exhaust-gas-analyzers to characterize how or if these species evolve downstream of the exhaust port during cold-start operation. A gasoline direct injected spark ignited (DISI) single cylinder engine was run at 2-bar net indicated mean effective pressure (NIMEP) at spark timings ranging from normal-SI operation relevant early spark timing of -10 degrees after top dead center firing (dATDCf) to more cold-start-relevant retarded spark timing of 25dATDCf. At the retarded spark timings, the exhaust manifold gas temperature increased downstream of the exhaust port indicating the presence of oxidation reactions that counteract heat transfer losses; a trend also supported by oxidation of total hydrocarbons (THC), CO, and H2 observed downstream of the exhaust port. Additionally, increase in NOx emissions downstream of the exhaust port indicated presence of high temperature required to drive NOx chemistry. Aromatics were the largest exhaust hydrocarbon species group detected at all spark timings, while the paraffins were under-represented from their fuel composition fraction. Organic carbon accounted for more than 95% of the PM mass at exhaust port for all spark timings. At retarded spark timings, the PM mass reduced downstream of the exhaust port primarily driven by organic carbon oxidation. Particle number and size measurements at retarded spark timings indicated a reduction in particle count downstream of the exhaust port with an accompanying increase in particle size possibly due to agglomeration.

Numerical Simulation of the Effect of Flow Velocity and Inlet Position on the Pressure Drop in the Exhaust Manifold

The exhaust manifold, also known as the exhaust header, is an important channel in the combustion chamber of a car. The exhaust manifold's role is to collect exhaust gas from various exhaust channels and direct it to the catalyst and car exhaust muffler for filtering. This research was conducted to see the pressure loss in the exhaust manifold at different speed conditions and different inlet positions on an engine with 4 cylinders. The speed variations used were 0.4, 0.6 and 0.8 m/s while the inlet position variations used were 1 and 3 and 2 and 4. The method used was numerical simulation. Geometry is created in the CAD software, then proceed with creating a mesh and setting boundary conditions. The results obtained show that the greater the flow rate, the greater the pressure drop. Based on the inlet position, positions 2 and 4 tend to have a greater pressure drop than positions 1 and 3 at each of the same speed. The largest pressure drop is 1.5438 Pa at a speed of 0.8 m/s with inlet channels 2 and 4.

Some Practical Hints on Preservation of Aircraft Engines Using a Rig from Corrosion Problems

Aircrafts need to be grounded for want of routine scheduled maintenance and inspection after certain period of flying hours. During such maintenance practices, the turbo-propeller engines are kept dismantled, un- installed and non-operative conditions for a longer period even up to two years. During this non-operative period, the engines and components are susceptible to extensive chronic corrosion hazards. To prevent this hazard, the engines and components are required to be preserved both internally and externally from corrosion that is the engine components such as turbine, turbine blades, compressor, fuel nozzles, fuel system pipelines, diffuser, combustion cum mixing chamber, expansion nozzle and exhaust manifold. Over the long experience of operating the aircrafts, it has been observed that the appliance provided by the manufacturer is only meant for internal corrosion preservation purposes of the operative and installed engines and cannot be used for external corrosion preservation of non-operative and un installed engines which led to drastic reduction of engine lives and unsafe operating conditions to the aircrafts due to inherent materialistic corrosive effects. The material of the turbine blades could not able to withstand its designed high combustion temperature due to the corrosion problems, which leads to unsafe engine conditions. The problem was attributable to the design factor that the high pressure cock in the fuel supply system could open and allow the preservative oil to enter into the main fuel system only when sufficient oil pressure is built up in associative oil system, which needs rotating the engines at least in idling speeds. Simulating this mandatory condition is not possible for the non-operative uninstalled engines. To overcome the corrosion hazard problem of aircraft engines, a bogie hinge joint flushing device has been designed, fabricated and tested using the local resources after taking into consideration of this important engine external preservation requirements, layout of the turbo-propeller engine power plant and fuel supply systems. This innovative external preservation rig has got multiple options coupled with internal preservation for preserving the engine components such as turbine, turbine blades, compressor, fuel nozzles, fuel system pipelines, diffuser, combustion cum mixing chamber, expansion nozzle and exhaust manifold during the course of long maintenance period. The newly designed and developed external preservation rig has resulted in achieving the complete external preservation requirements of following categories of turbo-propeller engines. a) New/overhauled engines in storage and kept on expiry of preservation life b)Installed engine required to be removed for storage but cannot be cranked or rotated c) Installed engines that are not in running condition/installation-seized engines d) Uninstalled engine for defect investigations/defect rectifications e) Non operative unsafe engines

Development of an experimental/numerical validation methodology for the design of exhaust manifolds of high performance internal combustion engines

Several typical failure modes in the exhaust manifold of an internal combustion engine are commented on. In particular, thermal loading and the related thermal fatigue damage mechanism are addressed. The component under investigation is a cast exhaust manifold including the turbine involute. Finite Element simulations are performed, and a numerical methodology is presented to interpret and understand the observed failures, with the aim of developing a useful tool to virtually validate the component, before the manufacturing phase. The Finite Element analysis closely mimics the experimental validation procedure that considers several heating and rapid cooling cycles to simulate typical engine operating conditions. A static mechanical characterization at high temperatures of the materials involved is carried out, aimed at identifying a suitable alloy and its mechanical characteristics useful for feeding the numerical models. The developed design methodology proposes a damage criterion for thermal fatigue investigation, considering the elastoplastic behaviour of the material when subjected to high temperature cycles. In particular, the accumulated equivalent plastic strain range for a single thermal cycle (ΔPEEQ) is used, following the Ferrari expertise. The methodology appears to be well correlated with the experimental evidence, thus limiting the number of tests necessary for the approval of the component.

Mechanical integrity and erosion resistance of 3D sand printing materials

3D sand printing, a binder jetting-based additive manufacturing process, can directly produce sand molds with complex geometries for high-quality and lightweight metal parts. However, there is still a lack of information on how to degrade and erode the mechanical integrity of 3D sand molds. Here, correlations have been investigated between 3D printing materials and various properties of 3D-printed molds: microstructure, flexural strength, reliability, and erosion resistance. As a result, given the mechanical strength and the formation of the binder necks, the most appropriate flexural strength of 4.2 MPa, reliability of 7.8, and high erosion resistance of 86% are achieved from the 3D-printed sand molds prepared with a binder of 2 wt% and an activator of 0.25 wt%. The exhaust manifold casted using a 3D-printed sand mold with optimum conditions, it shows the same or better performance than the genuine part.

Review and evaluation of metals and alloy’s compatibility with hydrogen-fueled internal combustion engines

Hydrogen internal combustion engines (H2-ICEs) are being examined primarily owing to their low criteria pollutants and zero carbon dioxide emissions. However, there are many components and systems of a H2-ICE (including, i.e., gaskets, fuel injection system, piston, cylinder head, exhaust manifolds,…) that are exposed to direct or indirect high-pressure and temperature hydrogen that can lead to deterioration and degradation of the materials, in particular rubbers, metals and their alloys. In the present article, the implications on the characteristics of metals and their alloys exposed to a hydrogen atmosphere are examined with reference to the typical materials and respective operating conditions found in H2-ICEs. The effects of direct or indirect exposure of high pressure and low/high-temperature hydrogen on the properties including mechanical properties of metals and their alloys have been explored. Finally, based on the previous review, a critical assessment of their suitability for a safe and reliable operation on H2-ICEs is provided.

Study on gasdynamic interaction in a regulated two-stage turbocharging turbines at pulsating conditions

Understanding the response of performance of two-stage turbine to pulsating flow in exhaust manifold system is essential for performance improvement of engine. This paper studies unsteady interaction of two turbines in a two-stage turbocharging system via experimental method and a reduced order model. Firstly, experimental results of the unsteady pressure ratio of two turbines are discussed in cases with different engine speeds, engine loads, and bypass valve openings. Results show that the pressure ratio distribution between two turbines is profoundly influenced by the engine condition. The pressure ratio of low-pressure turbine (LPT) increases consistently with the engine speed and load, while it increases slightly or even remains unchanged for high-pressure turbine (HPT). HPT is de-loaded when the bypass valve is open, and there are large numbers of fluctuations with high frequencies in the trace of pressure ratio when the bypass valve is open. Next, a reduced order model of the two-stage turbine is established for turbine responses at pulsating conditions, and model validations of performance and unsteady pressure in two-stage turbine all show high precision. Finally, the model is applied for performance analysis of two-stage turbine system under pulsating conditions. The results show that with the increase in engine speed, load or bypass valve opening, the hysteresis loops of both turbines are expanded around the steady performance curve. However, the deviation of cycle-average performance from steady case for two turbines is notably different. LPT shows a stronger throttling effect at pulsating inflows. Moreover, compared with steady performance for whole two-stage turbine, cycle-average performance is reduced for all pulsating cases, especially for cases of open valve. The differences in turbine performance of two-stage turbine system caused by gasdynamic coupling effect of two turbines are suggested to be considered in the turbo-engine matching.

INFLUENCE OF THE COMPOSITION OF THE SYNTHETIZED GAS ON THE COMBUSTION PROCESS OF THE MIXTURE IN THE INTERNAL COMBUSTION ENGINE

The article is devoted to the use of low-energy synthesized gas (synthesis gas) as a fuel for internal combustion engines, which in turn transmit mechanical energy to a cogeneration plant (combined production of heat and electricity). Such power plants allow you to achieve high values of total effective efficiency when using a conventional internal combustion engine with spark ignition. The analysed synthetic gases can be obtained by the method of gasification of household waste with access to air. In this work, synthesis gases were obtained in laboratory conditions. The composition of the components of the studied synthesis gases corresponds to several gas mixtures that are created during the artificial gasification of household waste of certain categories. The influence of the composition of the synthesis gas components on the internal parameters of the internal combustion engine was studied. The process of supplying fuel to the engine was controlled by a standard block with several sensors connected to it in the combustion chamber and the exhaust manifold. Engine operation on all synthesis gas mixtures was compared with operation on pure methane mixture. The analysis shows that the drop in efficiency indicators in the form of indicator mean effective pressure (IMEP) ranges from 10% to 40% compared to work on a pure methane mixture. With an increase in the proportion of hydrogen in the synthesis gas, the stiffness of the engine, as well as the rate of heat generation, increases. When the synthesis gas contained a high proportion of carbon monoxide, the stiffness of the engine was the lowest. The main combustion time of synthesis gas is reduced when hydrogen is added to the mixture, and due to an increase in the proportion of methane or carbon monoxide, it increases on the contrary. The presented results make it possible to analyses the processes occurring in the internal combustion engine, as well as the influence of the components of the synthesis gas produced from renewable energy sources. This will make it possible to adjust the gas production process in such a way as to achieve the highest possible energy and economic indicators of its utilization in the cogeneration plant.
 Keywords: internal combustion engine, synthesis gases, analysis of pressure

Effect of the Thermal Mean Stress Value on the Vibration Fatigue Assessment of the Exhaust System of a Motorcycle Engine

<div>The exhaust manifold of a high-performance motorcycle engine is subjected to combined thermal and vibrational loadings. In this research, the whole fatigue assessment of an exhaust manifold is addressed. First, a classic low-cycle fatigue analysis is performed. Then, a specific methodology for determining the fatigue cycle of components subjected to thermal and vibration loadings is developed and presented in a way that possible damages can be evaluated. The results are post-processed and the damage caused by fatigue cycles is computed referring to the Wöhler curve of the material using the Dirlik approach.</div>

An Experimental Study on the Conversion of CaO to CaSO4 During Diesel Particulate Filter Regeneration

The deposition of ash on a diesel particulate filter (DPF) results in an increase in pressure drop across the aftertreatment system, which leads to reduced capacity for soot and an increase in frequency of regeneration to eliminate the soot. To estimate the amount of ash and design a reduction method for the accumulated ash on the DPF, a deeper understanding of the ash generation mechanism is required. Previous studies have found that ash sampled at exhaust manifolds comprises metal sulfate and some oxides, whereas ash accumulated on DPFs primarily comprises typical metal sulfates. Although metal oxides are converted to the metal sulfates, the conversion mechanism is not well understood. Herein, the formation mechanism of calcium sulfate (CaSO4), which is the main component of ash on DPFs, from calcium oxide (CaO) was investigated using a flow reactor. CaO was made to react with SO2, SO3, O2, and H2O, when passed through a diesel oxidation catalyst. Quantitative analysis of the ash components in the products was performed using ion chromatography. The concentrations of SO2, SO3, and H2O during the reaction were analyzed by Fourier-transform infrared spectroscopy. Based on the experimental results, it was found that CaSO4 mainly formed from the reaction of CaO with SO2 and SO3; whereas, H2O inhibited CaSO4 formation owing to the change in physicochemical properties of CaO.

Investigation of flow distribution in energy intensive aluminium production reduction cells: An exploratory study

The process of making aluminium often involves electrolytic cells, also known as reduction cells. The reduction cell exhaust manifolds must achieve a steady distribution of exhaust from each cell in the network. This will prevent fugitive pollutants, which are harmful to both human and environmental health. While ducts are adjusted to achieve appropriate flow rates, they become asymmetrical over time. A few case studies available in the literature that discuss the flow distribution in an electrolytic cell, and almost none provide insight into the operational flow distribution of reduction cells in service. As part of this study, the operating flow distribution in service reduction cells is examined, determined which factors contribute to poor gas patterns produced by reduction line cells and analysed the flow conditions that result in sediment deposition within the ducting that connects the reduction cells to the superstructure, which is the novelty of this case study. Various instruments were used to record the temperature and pressure of a smelting facility. Flow information for each cell was collected using Pitot traverses. Infrared thermography of the ducts was used to locate temperature anomalies and possible areas of particle build-up. These tests indicated a number of probable contributing causes that have contributed to the inadequate airflow pattern from each reduction cell.