Local Temperature Peaks Research Articles

Chemical kinetics of Lean − Rich − Lean fuel-air staged NH3/H2-air combustion for emission control

Ammonia has garnered considerable attention among researchers as a carbon–neutral fuel option. Addressing the challenge of its inherently slow combustion kinetics, significant research efforts have been directed toward mitigating NOx emissions, which represents a critical hurdle in advancing the commercial viability of ammonia as a sustainable fuel. The rich-lean combustion approach has been advocated and demonstrated as the primary means to keep NOX within acceptable emission limits. However, in the current study, a distributed fuel and air injection strategy is proposed and investigated as a superior alternative compared to the traditional rich-lean method for NOX reduction for NH3/H2-air mixtures with higher ammonia fuel fraction (XNH3 = 50 − 90 %). The proposed lean-rich-lean strategy with multi-staging of fuel and air supply is achieved by injecting NH3-air mixtures into H2-air combustion products followed by a downstream supply of preheated dilution air. Such an injection strategy manages the surge of NHi and O/H radicals while avoiding local temperature peaks by implementing a two-stage ignition pattern of NH3/H2 blends combustion in series. NOX reductions of approximately 48 % and 7 % forXNH3 = 50 % and 70 %, respectively, is achieved with the lean-rich-lean combustion strategy compared to the rich-lean strategy over a wide range of global equivalence ratios(ϕG = 0.3 to 0.7). The lean-rich-lean combustion strategy for atmospheric NH3/H2-air swirl flames, when integrated with advanced SCR technology, is anticipated to demonstrate a viable approach to achieving zero carbon and low NOX emissions in industrial applications.

Exploring thermal effects of advanced backside power delivery network beyond 3 nm node

Backside Power Delivery Networks (BSPDNs) address scaling issues by relocating power, boosting efficiency and density. However, thermal effects pose challenges. In this work, a comprehensive thermal analysis of BSPDN is performed to elaborate the key modulation factors and possible optimization approaches, where the specific backside metal layers are constructed to investigate the impacts of operating conditions, via distribution and materials on thermal effects. To improve the simulation efficiency, the effective thermal conductivity is employed to simplify the Nanosheet (NSH) FET based front-end-of-line (FEOL) and other layers at the 3 nm technology node. Results show that non-uniform via distribution in BSPDN causes temperature fluctuations, but augmenting Backside Via counts effectively mitigates local peak temperature increases from higher power. For BSPDN, backside cooling solutions outperform frontside in efficiency, particularly at high via densities. Using high thermal conductivity inter-metal dielectric (IMD) materials significantly reduces global temperature rise and fluctuations from non-uniform vias in BSPDN, enhancing PDN design flexibility.

Heat-transfer fingerprint of Josephson breathers

A sine–Gordon breather is demonstrated to enhance the heat transfer in a thermally biased long Josephson junction. This solitonic channel allows for the tailoring of the local temperature throughout the system. Furthermore, the phenomenon implies a clear thermal fingerprint for the breather, and thus a ‘non-destructive’ breather detection strategy is proposed here. Distinct breathing frequencies result in morphologically different local temperature peaks, which can be identified in an experiment.

Study on heat transfer characteristics and enhancement mechanism of supercritical carbon dioxide in adaptive channels

Supercritical CO2 power cycles have promising applications in many fields, the heat transfer of supercritical CO2 is critical to the efficiency and safe operation of cycle system. The adaptive channel was previously proposed by our group to improve heat transfer of supercritical CO2, the performance of heat exchanger with adaptive channel was experimentally studied. Whereas the effect of adaptive channel on heat transfer deterioration of supercritical CO2 and the mechanism remain unclear. In this study, the effect of adaptive channel on heat transfer deterioration of supercritical CO2 and the mechanism are analyzed numerically based on a single channel, the effect of structure on heat transfer is analyzed through the maximum wall temperature and average heat transfer coefficient under the same length and heat transfer area. The results reveal adaptive channel is effective at alleviating heat transfer deterioration with no local peak in wall temperature distribution. The channel variation length of adaptive channel need to be increased from 0.4 to 0.8 with the aggravation of heat transfer deterioration in order to eliminate local wall temperature peak. For the heat transfer deterioration conditions, the maximum wall temperature lowers first and then increases as channel variation length increases, there is a length that makes the maximum wall temperature lowest, which is lowered by more than 40 °C compared with straight channel. The average heat transfer coefficient can be increased by 1.1 ∼ 1.5 times as channel variation length increases. For the no heat transfer deterioration conditions, the maximum wall temperature increases about 30 °C whereas average heat transfer coefficient can be increased by 58 %∼76 % with channel variation length increasing. The mechanism of adaptive channel alleviating heat transfer deterioration is as follows: the fluid velocity always presents an inverted U-shaped distribution along the radial direction in adaptive channel, the radial density difference is less and buoyancy effects heat transfer weakly. The turbulent kinetic energy is kept at high, so the heat near the wall is transferred to the main flow timely.

Multi-echo MR thermometry in the upper leg at 7T using near-harmonic 2D reconstruction for initialization.

The aim of this work is the development of a thermometry method to measure temperature increases in vivo, with a precision and accuracy sufficient for validation against thermal simulations. Such an MR thermometry model would be a valuable tool to get an indication on one of the major safety concerns in MR imaging: the tissue heating occurring due to radiofrequency (RF) exposure. To prevent excessive temperature rise, RF power deposition, expressed as specific absorption rate, cannot exceed predefined thresholds. Using these thresholds, MRI has demonstrated an extensive history of safe usage. Nevertheless, MR thermometry would be a valuable tool to address some of the unmet needs in the area of RF safety assessment, such as validation of specific absorption rate and thermal simulations, investigation of local peak temperatures during scanning, or temperature-based safety guidelines. The harmonic initialized model-based multi-echo approach is proposed. The method combines a previously published model-based multi-echo water/fat separated approach with an also previously published near-harmonic 2D reconstruction method. The method is tested on the human thigh with a multi-transmit array at 7T, in three volunteers, and for several RF shims. Precision and accuracy are improved considerably compared to a previous fat-referenced method (precision: 0.09 vs. 0.19°C). Comparison of measured temperature rise distributions to subject-specific simulated counterparts show good relative agreement for multiple RF shim settings. The high precision shows promising potential for validation purposes and other RF safety applications.

Flame Characteristics of Gasoline and a Water-in-Gasoline Mixture under a Controllable High-Temperature Thermal Atmosphere.

This study explores the flame characteristics of gasoline and a water-in-gasoline mixture and provides some optimization suggestions for the control strategy of water-in-gasoline mixture injection in the internal combustion Rankine cycle engines. The influences of co-flow temperature, injection pressure condition, and water content on the flame characteristics were investigated under a controllable high-temperature thermal atmosphere, including flame pattern, liftoff height, brightness, and local peak temperature distribution. Results obtained show that the water content has the most significant effect on the flame characteristics. The flame pattern gradually changes from slender to lumpy as the water content rises, while the high-temperature zone increases and becomes uniform. There is an appropriate water content range of 10-20% in which the flame characteristics are generally better. Furthermore, as the water content increases from 20 to 30%, the flame characteristics deteriorate, with a sharp decrease in the maximum flame temperature and brightness.

Numerical study on the effects of supercritical CO2-based nanofluid on heat transfer deterioration

The drastic variation of thermoproperties of supercritical CO2 may induce heat transfer deterioration (HTD). To solve the HTD problem, the effects of nanoparticles on supercritical CO2 heat transfer performance was numerically studied. Results show that with the increase of nanoparticle concentration, the local temperature peak is further suppressed. The wall temperature has a maximum decrease of 168.9 K, and the optimal heat transfer enhancement of the supercritical CO2 nanofluid has a maximum increase of 51.4%. Detailed flow field analysis indicates that the decrease of density gradient in the buffer layer significantly suppresses the coupling effect of buoyancy and flow acceleration, which leads to better heat transfer performance. Also, the convective heat transfer benefits from the reduced specific heat and improved thermal conductivity of nanofluid. Eventually, it is the high-density-nanoparticle rather than the high thermal-conductivity-nanoparticle that plays a more effective role in the mitigation of the HTD phenomenon.

Interfacial quality prediction model for Al/steel sheets during friction stir–assisted double-sided incremental forming with synchronous bonding

The widely investigated Al/steel laminated structures are challenged with subsequent plastic deformation due to the prone generation of interfacial brittle intermetallic compound layer. To overcome this drawback, a recently proposed thermomechanical forming technology as friction stir–assisted double-sided incremental plastic forming with synchronous solid-state interfacial bonding is utilized to fabricate Al/steel laminated structures. Typical interfacial bonding-forming performances produced by a series of experiments classified as sound bonding, de-bonding, over-thinning, penetration and crack are individually assessed. Local working peak temperature and maximum forming force in loading area are recorded and evaluated during stable bonding-forming stage. Considering the heat-force coupling effect, a pressure-strain-temperature–based prediction model is modified to assess interfacial quality, which is conformed to experimental results. This work can help obtain proper process window to successfully fabricate Al/steel laminated parts and shall also inspire to build guidance of related thermomechanical joining-with-forming processes to achieve high interfacial performance.

Comparative study of deposition patterns for DED-Arc additive manufacturing of Al-4046

Quality assurance is one of the largest challenges to the widespread adoption of metal additive manufacturing technology. Deposition pattern can significantly impact the temperature distribution during manufacturing process and thus the overall quality and residual stress formation of the manufactured components. In order to explore the intricate relationship, three different deposition patterns in DED-Arc additive manufacturing, the meander pattern, the spiral pattern and the newly developed S pattern, were experimentally and numerically scrutinized in terms of the resulting temperature distribution, grain size, porosity as well as residual stress formation. The study reveals that the variation of the deposition paths results in characteristic temperature fields and gradients with distinct local peak temperatures that determine the deposition quality, and simultaneously offers great degrees of freedom for optimal pattern design. Comparing the results with different deposition patterns, the S pattern leads to a more homogeneous temperature distribution, showing beneficial effects on the microstructure, porosity and residual stress formation in the deposited Al-4046 material, and is thus regarded as a promising alternative for improving additively manufactured parts quality.

Startup influencing factor investigation and quantitative interaction analysis on a loop thermosyphon with multiple evaporators

Loop thermosyphon with multiple evaporators has unique startup features and interaction characteristics between evaporators which are worth studying. In this paper, the startup influencing factors of a loop thermosyphon with multiple evaporators are studied experimentally and visually. Meanwhile, the interaction between evaporators is evaluated quantitatively using a newly defined parameter called interaction ratio, which represents percentage change in temperature divided by percentage change in heating power. The results show that the temperature of evaporators often has a local peak value during the startup, at which moment the boiling becomes fully developed. Also, the effect of filling ratio, heating power value and distribution on the local peak temperature is analyzed. For each evaporator, interaction ratio on itself is always the largest. Among the evaporators, interaction ratios of the evaporator in the middle are the largest because the competition and crowding of its flow with the other evaporators are more intense. With the increase of filling ratio, interaction ratios on itself decrease while interaction ratios on the others increase.

Development and CFD analysis for determining the optimal operating conditions of 250 kg/day hydrogen generation for an on-site hydrogen refueling station (HRS) using steam methane reforming

The objective of this study to develop and undertake a comprehensive CFD analysis of an effective state-of-the-art 250 kg/day hydrogen generation unit for an on-site hydrogen refueling station (HRS), an essential part of the infrastructure required for fuel cell vehicles and various aspects of hydrogen mobility. This design consists of twelve reforming tubes and one newly designed metal fiber burner to ensure superior emission standards and performance. Experimental and computational modeling steps are conducted to investigate the effects of various operating conditions, the excess air ratio (EAR) at the burner, the gas hourly space velocity (GHSV), the process gas inlet temperature, and the operating pressure on the hydrogen production rate and thermal efficiency. The results indicate that the performance of the steam methane reforming reactor increased significantly by improving the combustion characteristics and preventing local peak temperatures along the reforming tube. It is shown that EAR should be chosen appropriately to maximize the hydrogen production rate and lifetime operation of the reformer tube. It is found that high inlet process gas temperatures and low operating pressure are beneficial, but these parameters have to be chosen carefully to ensure proper efficiency. Also, a high GHSV shortens the residence time and provides unfavorable heat transfer in the bed, leading to decreased conversion efficiency. Thus, a moderate GHSV should be used. It is shown that heat transfer is an essential factor for obtaining increased hydrogen production. This study addresses the pressing need for the HRS to adopt such a compact system, whose processes can ensure greater hydrogen production rates as well as better durability, reliability, and convenience.

Influence of processing parameters on joint shear performance in laser direct joining of CFRTP and aluminum alloy

Laser direct joining of a carbon fiber reinforced thermoplastic (CFRTP) and an alloy is prone to thermal defects, thereby reducing the joint performance. This can be avoided by reasonably controlling the joining temperature. To this end, a process optimization method characterized by taking full control of the melting depth and local peak temperature is proposed for representative CFRTP/Al and CFRTP/polymer/Al stacks. For the first time, a temperature simulation model considering the heat transfer during the laser direct joining of heterogeneous CFRTP/alloy stacks is established; the average calculation error of the model is <10%. Based on the simulation results, regression models of the melting depth and local peak temperature are established. Subsequently, constraints are determined by defect distribution observation and joint fracture surface analysis; thus, the optimized ranges of the process parameters are obtained. Finally, through laser direct joining experiments, the improvement in the joint performance is demonstrated and analyzed. The results suggest an enhancement in the strength of the aforementioned stacks under the optimized process, thus proving the rationality of the proposed method by controlling the melting depth and local peak temperature, particularly for CFRTP/polymer/Al stacks with strength close to 30 MPa.

Microstructure and Local Mechanical Properties of the Heat-Affected Zone of a Resistance Spot Welded Medium-Mn Steel.

The properties of the heat-affected zone (HAZ) are reported to have a great influence on the mechanical performance of resistance spot welded advanced high strength steels. Therefore, in the present work, the HAZ of a medium-Mn steel is characterized regarding its microstructure and its mechanical properties depending on the distance to the fusion zone (FZ). In order to obtain the local mechanical properties of the HAZ, samples were heat-treated in a joule-heating thermal simulator using different peak temperatures to physically simulate the microstructure of the HAZ. By comparing the microstructure and the hardness of these heat-treated samples and the HAZ, the local peak temperatures within the HAZ could be determined. Subsequently, tensile tests were conducted, and the austenite phase fraction was measured magnetically on the physically simulated HAZ samples in order to determine the local mechanical properties of the HAZ. As verified by energy-dispersive X-ray spectroscopy, peak temperatures above 1200 °C led to a uniform distribution of manganese, resulting in a predominantly martensitic microstructure with high strength and low total elongation after quenching. Below 1100 °C, the diffusion of manganese is restricted, and considerable fractions of austenite remain stable. The austenite fraction increases almost linearly with decreasing peak temperature, which leads to an increase of the total elongation and to a slight decrease in the strength, depending on the distance to the FZ. Temperatures below 700 °C exhibit hardly any effect on the initial microstructure and mechanical properties.

Microstructural evolution and mechanical integrity relationship of dissimilar metal welding between 2205 duplex stainless steel and composite bimetallic plates

In this paper, shielded metal arc welding on the dissimilar joint between 2205 duplex stainless steel and composite bimetallic plates (304 L stainless steel/10CrNi3MoV steel) with a filler metal E2209 was performed. Furthermore, the microstructure, phase, mechanical properties and intergranular corrosion resistance of the joints were investigated and element distributions of the interfaces were characterized. The results show that austenite transformed to ferrite under the influence of welding thermal cycle, and then a large amount of ferrite appeared in heat affected zone (HAZ) of 2205 duplex stainless steel. Coarse bainite grains were formed in HAZ of the 10CrNi3MoV steel near the fusion line with high temperature welding thermal cycle. Fine granular bainite was also generated in HAZ of 10CrNi3MoV steel due to the relatively short exposure time to the active temperature of grain growth. Local peak temperature near the base 10CrNi3MoV steel was still high enough to recrystallize the 10CrNi3MoV steel to form partial-recrystallization HAZ due to phase change. The filler metal was compatible with the three kinds of base materials. The thickness of the elemental diffusion interfaces layers was about 100 µm. The maximum microhardness value was obtained in the HAZ of 2205 duplex stainless steel (287 ± 14 HV), and the minimum one appeared in HAZ of SS304L (213 ± 5 HV). The maximum tensile strength of the welded joint was about 670 ± 6 MPa, and the tensile specimens fractured in ductile at matrix of the composite bimetallic plates. The impact energy of the weld metal and HAZ of the 10CrNi3MoV steel tested at –20 °C were 274 ± 6 J and 308 ± 5 J, respectively. Moreover, the intergranular corrosion resistance of the weldment including 304 L stainless steel, weld metal, HAZs and 2205 duplex stainless steel was in good agreement with the functional design requirements of materials corrosion resistance.

Experimental Observation of Magnetic Island Heteroclinic Bifurcation in Tokamaks.

We report empirical observations of magnetic island heteroclinic bifurcation for the first time. This behavior is observed in interacting coupled 2/1 tearing modes in the core of a DIII-D tokamak plasma. Poincaré maps constrained by measured magnetic amplitudes and phasing show bifurcation from heteroclinic to homoclinic topology in the 2/1 island as the 4/2 relative amplitude (R_{4/2}) decreases. Initially, the local electron temperature peak in the 2/1 island splits, consistent with two O points. As R_{4/2} decreases a single peak forms, consistent with one O point. These call for developing tearing stability theory and control solutions for heteroclinic islands in tokamaks.

Development of a Continuous Pulsed Electric Field (PEF) Vortex-Flow Chamber for Improved Treatment Homogeneity Based on Hydrodynamic Optimization.

Pulsed electric fields (PEF) treatment is an effective process for preservation of liquid products in food and biotechnology at reduced temperatures, by causing electroporation. It may contribute to increase retention of heat-labile constituents with similar or enhanced levels of microbial inactivation, compared to thermal processes. However, especially continuous PEF treatments suffer from inhomogeneous treatment conditions. Typically, electric field intensities are highest at the inner wall of the chamber, where the flow velocity of the treated product is lowest. Therefore, inhomogeneities of the electric field within the treatment chamber and associated inhomogeneous temperature fields emerge. For this reason, a specific treatment chamber was designed to obtain more homogeneous flow properties inside the treatment chamber and to reduce local temperature peaks, therefore increasing treatment homogeneity. This was accomplished by a divided inlet into the chamber, consequently generating a swirling flow (vortex). The influence of inlet angles on treatment homogeneity was studied (final values: radial angle α = 61°; axial angle β = 98°), using computational fluid dynamics (CFD). For the final design, the vorticity, i.e., the intensity of the fluid rotation, was the lowest of the investigated values in the first treatment zone (1002.55 1/s), but could be maintained for the longest distance, therefore providing an increased mixing and most homogeneous treatment conditions. The new design was experimentally compared to a conventional co-linear setup, taking into account inactivation efficacy of Microbacterium lacticum as well as retention of heat-sensitive alkaline phosphatase (ALP). Results showed an increase in M. lacticum inactivation (maximum Δlog of 1.8 at pH 7 and 1.1 at pH 4) by the vortex configuration and more homogeneous treatment conditions, as visible by the simulated temperature fields. Therefore, the new setup can contribute to optimize PEF treatment conditions and to further extend PEF applications to currently challenging products.

Experimental study on the influence of obstacle aspect ratio on ethanol liquid vapor deflagration in a narrow channel

A series of experimental tests were conducted in a narrow obstructed channel to investigate the influence of obstacle distribution mode (unilateral and bilaterally symmetrical distribution) and obstacle aspect ratio (the width-to-height ratio in flame propagation direction) on vapor deflagration. Rectangular obstacles with different aspect ratios 0.9–2.1 were used. The flame propagation speed, flame front structure, overpressure and local temperature near obstacles were recorded and analyzed. The results indicated that different obstacle distribution modes would not fundamentally alter the propagation mechanism of deflagration flame and overpressure. The shear action of obstacle edges and the confined space structural form between the obstacle and the channel boundaries both exerted a significant effect on deflagration flame propagation. And two acceleration stages existed in the deflagration, and the flame speed peaks appeared above obstacle and near the channel portal, respectively. Specifically, when aspect ratio was 1.8, the maximum flame speed peaked to 102.5 m/s. Moreover, obstacle aspect ratio has shown a significant influence on flame front, and the flame front structure experienced complex changes as it passed through obstacle. What's more, an interesting reverse flame phenomenon was observed, which resulted in a larger area of violent flame combustion. The maximum length of reverse flame decreased firstly and then increased with the increase of obstacle aspect ratio, which probably ascribed to the inertial force of fluid. Accordingly, a simple empirical equation was proposed to predict the reverse flame length during flame propagation in the narrow obstructed channel. This equation performs well in prediction of reverse flame length in current application range. Meanwhile, the local temperature peak is closely related to the local deflagration reaction intensity affected by obstacle aspect ratio. In addition, it is also found that the deflagration overpressure and flame propagation involved the obvious coupling mechanism. Deflagration overpressure and flame speed reached peaks almost simultaneously. This coupling mechanism could significantly expend the impact range of deflagration.

Bead by bead study of a multipass shielded metal arc-welded super-duplex stainless steel

The present study aims at investigating bead geometry and the evolution of microstructure with thermal cycles in multipass shielded metal arc welding of a V-groove 13-mm type-2507 super-duplex stainless steel (SDSS) plate. The weld consisted of 4 beads produced with arc energies of 0.81–1.06 kJ/mm. The upper beads showed lower base metal (BM) dilution than the first bead. Thermal cycles were recorded with thermocouples, indicating that the cooling rate decreased in the as-deposited weld zone when adding a new bead. Ferrite fraction in the as-welded condition was lower for the upper beads. The austenite grain morphology in reheated passes varied depending on the local peak temperatures and the number of reheating passes. Sigma phase precipitated in a location reheated by the third and fourth passes that was subjected to a critical peak temperature for sigma precipitation. Ferrite content, measured using image analysis and Fisher FERITSCOPE technique, showed that the ferrite fraction moved toward 50/50% in the weld metal with an increasing number of reheating cycles. Finally, a schematic map showing an overview of the microstructure in the multipass SDSS weld was introduced.

Reduced-resolution RANS approach to grid spacer fuel assemblies

One of the main issues in the context of the safety assessment of liquid metal-cooled reactors is flow blockages in fuel sub-assemblies. CFD modelling may be used to predict the temperature and velocity fields inside a fuel assembly under blocked and unblocked conditions. However, the computational cost requirements make it infeasible to model the complete assembly using the resolved RANS, LES or DNS approaches. To this end, a reduced-resolution RANS approach of an assembly is presented and validated in this paper.In order to reproduce and compare with experimental data, the 19-pin hexagonal fuel assembly of the NACIE-UP facility at ENEA in Italy has been selected for the present simulation study. For the flow blockage, a 6-pin edge-type blockage is selected similar to that used in the experimental facility. During the pre-test simulation study, wall-resolved RANS simulations are performed for the unblocked flow conditions. Using the wall-resolved RANS simulations as reference, a mesh sensitivity is performed by subsequently reducing the wall and bulk resolutions. As the blocked flow condition requires transient simulations, the resolution study is only performed for the unblocked flow condition to reduce the computational effort. It is shown that the approach may be used to reproduce the temperature and velocity fields similar to that in wall-resolved simulations within tolerance limits, but at a fraction of the computational cost.Experimental data for unblocked and blocked flow conditions has been made available for the Blocked Fuel Pin Simulator (BFPS) section at the NACIE-UP facility. These experimental data are used to validate the reduced-resolution approach in the post-test analysis. The difference between the present results and the experimental data is attributed for and quantified. Consistent with the literature, two main effects of flow blockages are identified. A local temperature hotspot is observed in the wake of the blockage caused by the coolant recirculation zone. The global effect of temperature peak is observed at the end of the active length downstream of the blockage, caused by the lower mass flow rates in the blocked sub-channels. For the unblocked flow condition, the maximum difference compared to the experimental data is estimated to be 11%. While the error in prediction of the local temperature hotspot and peak temperature at the end of active length is estimated to be 25% and 12%, respectively, for the partially-blocked flow condition. Finally, based on the 19-pin model, the feasibility of the reduced-resolution approach for the complete 127-pin assembly of ALFRED demo reactor is demonstrated. In addition to the unblocked flow condition, the approach is also used for blocked grid spacer conditions. Consistent with the results of NACIE bundle, the two main effects – local and global – of the flow blockage are also observed here. The local effect of temperature hotspot behind the blockage is observed to be dominant for the larger blockage, while the global effect of peak temperature downstream of the blockage is observed to be proportional to the size of the flow blockage.

On the Combination of fuel-rich/lean burner with MILD combustion for further NOx emission reduction

Moderate or Intensive Low-Oxygen Dilution (MILD) combustion as a newly developed technology has drawn much attention all over the world since it features the homogeneous combustion and extremely low NOx emission. Even though reduced NOx emission is reported in pulverized coal MILD combustion, its performance is not as comparable as that of gaseous and liquid fuels. In order to investigate the possibility of further reducing NOx emission in a MILD coal combustion furnace, horizontal fuel-rich/lean burner as another promising technology aiming to regulate NOx emission is employed in this study. Results have shown that fuel-rich/lean burner is able to further reduce NOx emission by about 4% when applied to a MILD coal combustion furnace. This is due to the combined effect of the reduction of thermal- and fuel-NO formation. Particles entrained in the fuel-rich stream is heated in a reducing atmosphere, so that the oxidation of hydrogen cyanide (HCN) and ammonia (NH3) released by volatile is hindered. Moreover, the NO released by char is reduced to molecular nitrogen. Thermal-NO is reduced because of the low local peak temperature in both streams.