Hole Diameter Research Articles

Young's Modulus Characterization of Nano‐Level Silicon Nanomembrane

Silicon nanomembrane (SiNM) has drawn great attention for the application in nanoelectrical devices as it shows excellent flexibility and is compatible with the integrated circuit process. The mechanical property measurement of the SiNM with nanoscale thickness is critical. A suspended SiNM (40 nm thick) for mechanical measurements is fabricated by transferring a chemically etched ultrathin monocrystalline silicon film from silicon on insulator wafer to a substrate with a multi‐hole array. And then, the atomic force probe is utilized to load force on the free‐standing SiNM to obtain a force deflection curve, and then the Young's modulus of such floating SiNM can be directly calculated based on the large deflection plane model. It shows that the Young's modulus of such SiNM is basically consistent with that of the bulk silicon. However, the SiNMs’ floating area significantly affects the results, i.e., the Young's modulus varies with the ratio of the suspended area diameter (i.e., hole diameter) to the film thickness. The Young's modulus is independent of hole diameter when the ratio is greater than 425. According to this relationship, the variation of Young's modulus can be predicted for arbitrary thick SiNMs and any transferable nanofilms.

Design and numerical analysis of a novel argon gas tube to reduce impurities in large size casting crystalline silicon furnace

A novel design of argon gas tube within the silicon casting system was developed employing pipe flow and side jet analysis, which facilitates horizontal ejection of argon gas along the silicon melt surface. The aim was to enhance control over gas flow velocity for removing impurities during large size silicon ingot (1400 kg) growth, with special attention on the edge region of ingot. It was found that the diameter of side-facing outlet holes, when oriented along the corner direction, is about 2 times of that along the side center direction, to achieve an extended jet distance reaching corner region. The gas flow and transport of SiO above the silicon melt surface were studied for the proposed gas tube configuration based on 3D numerical simulations. The simulation results reveal the correlation between argon flow rate and resultant gas velocity at the edge of melt surface, which is consistent with the theoretical analysis, particularly for moderate to high argon flow rates. The numerical simulations demonstrated that the proposed gas tube, equipped with eight optimized outlet holes, outperformed the conventional tube in extracting SiO from both central and corner regions above the silicon melt surface.

Influence of pulse-tail energy of short-pulse CO2 laser in drilling of various glasses

In a short-pulse CO2 laser based on discharge excitation, there is a pulse tail that depends on the device configuration and operating conditions. The pulse tail is longer than the spike pulse and causes thermal effects such as a crack, heat-affected zones (HAZ), and so on. There are various types of glass having different physical constants related to heat, such as the thermal expansion coefficient and the softening point. Even if the same CO2 laser pulse is radiated onto glass, the processing results may differ depending on the glass material. Four types of glass, namely, crown glass, soda-lime glass, borosilicate glass, and synthetic quartz glass were irradiated with two types of short CO2 laser pulses, one with a large pulse tail and one with a small pulse tail, at a repetition rate of 200 Hz and a fluence per pulse of 22 J/cm2. As the processing characteristics, the ratios of the surface hole diameter and the HAZ diameter to the irradiation diameter, as well as the drilling depth, were investigated. The pulse-tail energy of the short CO2 laser pulses did not affect the surface hole diameter. In the glasses with small softening points of 740 °C or less, the pulse-tail energy of short CO2 laser pulses affected the HAZ with a large number of pulse irradiations with a total irradiation fluence of 2000 J/cm2 or more. The short CO2 laser pulses with a small tail produced a smaller HAZ than the short CO2 laser pulses with a large tail. In drilling with a large number of pulse irradiations, the short CO2 laser pulses with a small tail produced deeper drilling than the short CO2 laser pulses with a large tail. The glass material did not affect the surface hole diameter and the drilling depth. The glass material affected the HAZ.

Dynamic Characteristics Study of Elastic Ring Squeeze Film Damper with Rigid–Elastic–Oil Coupled Model

Due to the coupling of the damper journal with the elastic ring and oil film, the elastic ring squeeze film damper (ERSFD) shows better dynamic performance in comparison with the traditional squeeze film damper (SFD). Therefore, a novel rigid–elastic–oil coupled mathematical model was established. The elastic ring deformation, as the key point, is solved according to the planar bending theory. Then, based on the pressure governing equation of the oil film, using the central finite difference method, the oil film pressure was addressed. Meanwhile, the Simpson method was implemented to calculate the dynamic characteristic coefficients (equivalent stiffness and damping Ce) of ERSFD (DCCEs). Also, we analyzed the influence of journal eccentricity, oil film radius clearance, flexibility coefficient and damping hole diameter on the DCCEs, and the results were compared and verified with the existing literature. The sensitivity of each parameter to the DCCEs was analyzed by using the linear regression method. According to the results, the flexibility coefficient has the greatest effect on the DCCEs, followed by the oil film radius clearance. The eccentricity of the journal and damping hole diameter have the least impact. This work will provide a theoretical basis for reflecting on the bearing dynamic characteristics more truly and accurately.

Effects of ceramic fillers on failure loads and failure mechanisms of laminated composites with two-parallel pin-loaded holes

In this study, the failure load values and failure mechanisms of ceramic materials filled E-glass/epoxy laminated composite plates that have two-parallel circular holes, subjected to tension forces by two-parallel rigid pins, are investigated experimentally. The composite plates used in the pin tests were produced by using three different ceramic fillers, which are Silicon Carbide (SiC), Boron Carbide (B4C), and Aluminum Oxide (Al2O3). The weight fractions of ceramic fillers in each composite plate are 5%, 10%, and 15%. For evaluating the influence of joint geometry on failure loads and failure mechanisms, the edge distance-to-hole diameter ratio, different pin-hole diameters, and the ratio of the distance between the side edge of the sample and the center of pin-hole to the hole diameter were considered as geometric parameters. The results from the experimental tests revealed that adding ceramic fillers to the composites up to a certain ratio leads to a remarkable increment in the failure load values of the composites compared to the neat (0 wt.%) composites for all weight fractions. Further, the ultimate failure load values were obtained for composite plates filled with Al2O3 ceramics in 10% weight fractions.

Numerical simulations on the performance of transpiration cooling implemented with perforated flat plates

Transpiration cooling is an effective method of protecting high-temperature components. However, this technology is currently not applicable to turbine blades because conventional sintered porous materials cannot precisely control the geometric parameters of the cooling channels and coolant outlets. In this study, numerical simulations using the conjugate heat transfer method were conducted to study the effects of hole diameter, injection ratio, and mainstream Reynolds number on the cooling performance of perforated flat plates. A novel optimisation method for the overall transpiration cooling efficiency that reduces coolant consumption through a nonuniform coolant allocation strategy was proposed. The effects of different pore diameters (0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm) on transpiration cooling were investigated numerically. The results revealed that the hole diameter had a marginal effect on the average cooling efficiency of transpiration cooling under the same coolant-injection ratio. With dense heat transfer occurring within the solid matrix, the influence of variations in the pore size was diminished. However, the nonuniformity of the cooling efficiency on the hot wall surface increased with increasing pore size. A double coolant chamber non-uniform injection was adopted for the 0.3 mm perforated plate. The results indicated that there is an optimum coolant allocation ratio for achieving the highest average cooling efficiency with a certain coolant.

Measurement and modeling the suction force on ellipsoidal particles

The lack of suction force models for non-spherical particles represents a research gap, although non-spherical particles in a suction flow are encountered in numerous applications. The present work demonstrates the need to develop dedicated suction force models because previous approaches did not yield clear results. This study used a custom-made suction force measurement device to measure the suction force on ellipsoidal particles. A preliminary suction force model is proposed based on dimensional analysis and the modified Murphy theorem. The model considers the vacuum pressure (P), fluid density (ρg), fluid viscosity (μg), long axis length of the particle (Lp), distance between the particle center and the suction hole (x), incident angle (θo), particle equivalent diameter (de), and suction hole diameter (D). The model validation shows high prediction accuracy within ±10% deviation, and the application scope is 0.5 ≤ x/Lp ≤ 0.7, 0 ≤ θo ≤ 28, 0.7 ≤ de/Lp ≤ 0.9, 0.4 ≤ D/Lp ≤ 0.6, and 3.36 × 104 ≤ LpP0.5ρg0.5/μg ≤ 5.13 × 104. Moreover, the suction force does not increase with an increase in the particle's windward area. A piecewise function is constructed to consider the relationship between suction force and θo based on experimental data and computational fluid dynamic (CFD) simulations.

The Biomechanics of the Transpedicular Endoscopic Approach.

Biomechanical cadaveric study. The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8mm) and compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated. Clinical studies have repeatedly highlighted the benefits of endoscopic transpedicular decompression for downmigrated lumbar disc herniations. However, the biomechanical effects on pedicle stability have not been studied up to now. Twenty-four vertebras originating from four fresh-frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the tunneled pedicle on one side, and (2) the native pedicle on the other side. Twelve lumbar vertebrae were assigned to drill diameter of 6mm and the other 12 to diameter of 8mm. The median ratio of sustained force for the operated side compared with the intact contralateral side is equal to 74% (63-88) for both drill diameters combined. An 8mm transpedicular approach recorded an axial resistance of 77% (60-88) compared with the intact contralateral side ( P =0.002). A 6mm approach resulted in an axial resistance of 72% (66-84) compared with the intact opposite side ( P =0.01). No significant difference between the two different drill diameters was recorded ( P =1). For all three subgroups (intact, 8mm, 6mm) the Hounsfield units-values and the absolute resistance force showed significant correlations (intact: ρ=0.859; P <0.001; 8mm: ρ=0.902; P <0.001; 6mm: ρ=0.835; P <0.001). The transpedicular approach significantly reduces the axial resistance force of the pedicle, which may lead to pedicle fracture. Bone quality correlated positively with the absolute resistance force of the pedicle, whereas the influence of the drill hole diameter plays only a limited role.

Design of graded-index-type photonic crystal fiber with uniform air hole diameter and its application to collimator for single-mode photonic crystal fiber

Design of graded-index-type photonic crystal fiber with uniform air hole diameter and its application to collimator for single-mode photonic crystal fiber

Mechanical design and energy absorption performances of novel plate-rod hybrid lattice structures

Hybrid lattice structures, integrating diverse structural components from fundamental lattice topologies, have attracted significant attention for their exceptional mechanical properties encompassing elastic modulus, yield stress, and energy absorption. To amalgamate the lightweight characteristics of rod structures with the robust mechanical properties of plate structures, a novel plate-rod hybrid lattice (PRHL) with controllable geometrical parameters and higher energy absorption was proposed and fabricated via the Selective Laser Sintering technique. In the PRHL design, the hybrid rod structure, interlinked with the center of each surface of the semi-open Octet plate lattice (SOPL), mutually provides support and deformation constraints. To identify the mechanical properties of PRHL, quasi-static uniaxial compression tests of PRHL samples sintered by Polylactic Acid powder were carried out. In comparison to SOPL, the newly proposed PRHL demonstrates an approximate 13.4% improvement in initial crush stress and an 18.5% increase in specific energy absorption capacity. Furthermore, numerical simulations incorporating the effect of printing orientation were performed to analyze the deformation mechanism of the PRHL structures. The present study also underscores the capacity to fine-tune the mechanical properties of PRHLs by regulating the plate thickness, rod diameter and excavated hole diameter.

FLUID CHARACTERISTICS AND POLISHING EXPERIMENT OF INCLINED HOLE ARRAY USING ABRASIVE WATER FLOW

Inclined hole arrays on superalloys have important applications in aeroengines. However, defects occur during fabrication of inclined holes using thermal drilling methods, i.e. electrical discharge drilling (EDD), including a recast layer and microcracks on the hole wall. Therefore, abrasive water flow polishing (AWFP) of a superalloy inclined hole array machined via EDD was investigated in this study. Two types of specimens were designed: a hole array of identical size and a hole array with an identical inclination angle. The fluid simulation revealed that the fluid velocity and pressure on the lower edge of the inclined hole were significantly higher than those on the upper edge when the fluid flowed forward. The fluid characteristics exhibited opposite trends when backward flow was implemented. Time-division bidirectional flow can effectively compensate for flow field nonuniformity and improve material removal consistency during polishing. The experimental results show that for inclined holes with identical inclination angles, the size expansion decreases with an increase in the hole diameter owing to the lower fluid velocity and material removal volume in the relatively larger holes. Consequently, surface roughness Ra increases with hole size. For inclined holes with identical diameters, the size expansions of the entrance and exit approach the same level; whereas, Ra decreased with an increase in the inclination angle. The hole taper slightly reduced in all cases. Using garnet abrasives with 1300 mesh size, 1.5 wt.% abrasive concentration, and 3 MPa fluid pressure, the surface roughness Ra of target holes was reduced from pre-polishing [Formula: see text] 5.0 [Formula: see text]m to approximately post-polishing 1.0 [Formula: see text]m. The recast layer on the hole wall caused by EDD was completely removed.

Research on thermal performance and pressure loss of a new perforated-folded baffle solar air collector

In order to further improve the heat collection performance of solar air heaters and reduce internal pressure. This study establishes a collector with perforated baffle based on baffled collector. The model was simulated using CFD software. Fit and analyze the efficiency of the collector with the hole-opened rate (the ratio of the opening area to the baffle area). The results show that compared with non-perforated baffle collectors, perforated baffle collectors have lower pressure loss, higher collection efficiency, lower heat dissipation coefficient of about 37.58%, and higher heat transfer coefficient of about 10.51%. When the hole height is 30 mm, the hole diameter is 80 mm, and the hole-opened rate is 0.24, the coupling between heat collection efficiency and pressure loss is the best, which is 64.11% and 4.32 Pa, respectively. The heat collection efficiency decreases with the increase of porosity, and the fitting degree R 2 = 0.98. The deviation of fitting curve (between turbulence intensity and hole-opened rate) is less than 10%. Nusselt number increases gradually with the increase of Reynolds number. Fitting correlation between Nusselt number and Reynolds number, and fitting degree is 0.9985. Perforated-folded baffle collector provides theoretical basis for improving the solar thermal utilization rate.

Investigation of the drilling behavior of the Ti6Al4V alloy and developing prediction model using artificial neural network

This study investigates the influence of cutting parameters on drilling performance for Ti6Al4V alloy using TiN-coated carbide drill bits in a dry drilling environment. The surface roughness, feed force, cutting moment, cutting temperature, tool performance, hole diameter, circularity, and cylindricity values of the hole were studied. The optimal drilling parameters were determined using ANOVA to achieve the desired hole sizes, and prediction models were developed using artificial neural networks (ANN). The experimental results revealed that the feed rate was the most influential parameter for feed forces (92%), whereas the cutting speed had the greatest effect on tool performance (98%). It was determined as a result of the analyses that the optimal feed rate for tool performance, cutting moment, surface roughness, cutting temperature, and feed forces was 0.05 mm/rev. The diameter of the hole was positively affected at high cutting speeds and feed rates. The circularity and cylindricity of the hole were adversely affected by these cutting conditions. Adhesive wear was seen on the drill bits in all cutting conditions, and surface roughness was negatively affected by this adhesive wear. Artificial neural networks (ANN) were used to predict operating cost outputs (feed force, tool performance) and hole quality outputs (surface roughness, deviation of hole diameter). The compatibility of the experimental results and the ANN model was examined in the control experiment. ANN was able to predict the surface roughness and hole diameter with deviation values of 3% and 7%, respectively. Similarly, the deviation values for feed force and tool performance were determined at 3% and 10%, respectively.

Lab Experiments for Abrasive Waterjet Perforation and Fracturing in Offshore Unconsolidated Sandstones

Multistage hydraulic fracturing has been proven to be an effective stimulation method to extract more oil from the depleted unconsolidated sandstone reservoirs in Bohai Bay, China. The offshore wellbores in this area were completed with a gravel pack screen that is much too difficult to be mechanically isolated in several stages. Hydra-jet fracturing technology has the advantages of multistage fracturing by one trip, waterjet perforation, and hydraulic isolation. The challenges of hydraulic-jet fracturing in offshore unconsolidated sandstone reservoir can be summarized as follows: the long jet distance, high filtration loss, and large pumping rate. This paper proposes full-scale experiments on the waterjet perforation of unconsolidated sandstone, waterjet penetration of screen liners and casing, and pumping pressure prediction. The results verified that multistage hydra-jet fracturing is a robust technology that can create multiple fractures in offshore unconsolidated sandstone. Lab experiments indicate that the abrasive water jet is capable to perforate the screen-casing in less than one minute with an over 10 mm diameter hole. The water jet perforates a deep and slim hole in unconsolidated sandstone by using less than 20 MPa pumping pressure. Recommended perforating parameters: maintain 7% sand concentration and perforate for 3.0 min. Reduce sand ratio to 5%, maintain 3.0 m3/min flow rate, and continue perforating for 7.0 min. The injection drop of the nozzle accounts for more than 62% of the tubing pump pressure. The recommended nozzle combinations for different fracturing flow rates are 8 × ø6 mm or 6 × ø7 mm for 2.5 m3/min and 3.0 m3/min, and 8 × ø7 mm for 3.5 m3/min and 4.0 m3/min. A one-trip-multistage hydra-jet fracturing process is recommended to be used for horizontal wells in offshore unconsolidated sandstone reservoirs.

Casting of film-cooling holes for single-crystal blades

The flawless formation of film-cooling holes (FCHs) is critical for manufacturing single-crystal blade. Presently, high-energy beam drilling is mostly used to process gas film holes, which introduces the limitations of complex hole structures that are difficult to form and processing thermal defects that are difficult to eliminate. This study demonstrates an approach to form FCHs using casting, where an indirect additive manufacturing technology using a core/shell integral ceramic mold is applied for casting. Cylindrical 0.4, 0.8, and 4.0 mm-diameters hole are cast. The influence of fine ceramic cores on the microstructure of single-crystal blades during directional solidification is investigated using simulations and experiments. The fine ceramic cores of the FCHs affect the growth morphology of dendrites around the hole, which is determined by the hole diameter, primary dendrite spacing, and local temperature filed. Owing to the thermal conductivity difference between the alloy and ceramic, the local temperature filed around the holes changes abruptly, leading to the formation of shrinkage porosity and cavities. Furthermore, the process window for the casting of FCHs is determined using the longitudinal temperature gradient (GZ) and solidification rate (VZ). The proposed approach is of practical significance for the defect-free casting of tiny structures in single-crystal blades.

Manufacturing and Testing a Double Action Feed Pellet Durability Measuring Device

The experiment was aimed to evaluate a locally manufactured a dual-action device used for measuring feed pellets durability. The device performs dropping process in conventional devices, then sifting process to separate the pellets from the crumbles simultaneously, with a control the motor speed by using the pulse width modulation (PWM) Technique. The device performance was compared with the durability measuring device of a moving drop box. Rotational speed, diameter of the die holes of the machine was used in this study. The results showed that increasing the rotational speed of the die from 280 to 300 and to 320 rpm, increasing the die holes diameter from 3 to 4 and to 5 mm, led to a significant decrease in the feed pellets durability, for both devices. The lowest die speed of 280 rpm, the minimum diameter of the die holes of 3 mm, recorded the highest pellets durability of 94.45% with the test speed of 33 rpm for the dual action measuring device as well as 93.45% for the movable drop box device. A highly significant correlation was found between data of the both devices. Test device success was proven for measure feed pellets durability.

Experimental investigations on flow characteristics of impingement/swirl cooling structures inside a blade leading edge

Experimental investigations were conducted to study the flow characteristics of impingement/swirl cooling structures inside a turbine-blade leading edge (LE) using particle image velocimetry. The Reynolds number (Re) was maintained at either 10 000 or 20 000. The effects of Re and the ratio of the impingement-cooling (IC) hole offset distance to the IC hole diameter (e/d) on the flow phenomena and the characteristics of the impingement/swirl cooling structures inside the blade LE were analyzed. The effects of the coolant-outflow mode were also taken into consideration. The results show that when e/d = 0, the diffusion flow of the impingement jet moves more to the side of the LE with a larger rounded corner, and this phenomenon is particularly obvious at Re = 20 000. Regardless of the e/d value, both the impingement-jet velocity and vorticity increase significantly at a higher Re value. The velocity of the impingement jet reaching the internal impingement target surface of the LE decreases significantly as e/d is changed from 1.5 to −1.5 with Re = 20 000. Generally speaking, regardless of the e/d value, the impingement jet can form a swirling vortex on the side with the larger rounded corner. Under the conditions of Re = 20 000 and e/d = 1.5, regardless of the coolant-outflow mode, the flow velocity of the impingement jet decreases monotonically along the flow direction, and this is more obvious inside the LE model without film-cooling holes.

Simulation study on flexural behaviour of perforated aluminium tubes

A numerical investigation was conducted to compare the flexural capacity of AA6063-T5 aluminum alloy tubes with perforations of different hole diameters (4, 6, 8, and 10 mm), hole spacing (13-26-39-52 mm) and tube wall thickness (0.5, 1, 1.5 and 2 mm) by the finite-element analysis (FEA). As the tube thickness increases, the load-carrying capacity decreases, while the LCC increases as the hole diameter increases. It was observed that the LCC increased as the distance between the holes increased. ANOVA test was used to analyze the influence of hole diameter, hole spacing, and tube wall thickness on tube load-carrying capacity. It is found from the statistical analyses that the most significant factor on maximum load is tube thickness (97.2 %) between parameters of hole diameter, hole spacing, and tube wall thickness. As a result of the second statistical analysis, the most significant factor on maximum load is hole diameter (73.14 %) between parameters of hole diameter and hole spacing. A second important factor is hole spacing on maximum load.

Numerical Simulation and Experimental Study on Detecting Effective Prestress of 1860-Grade Strands Based on the Drilling Method

In this paper, we study the magnitude of the effective prestressing force of steel strands in prestressed reinforced concrete structures. Through the theory of micro-hole release, the functional relationship equation between tensile stress and strain-containing coefficients A and B is established. Then, Midas FEA NX 2022 (v1.1) finite element software is used to establish the stress-release model of strand drilling holes and analyze the influence of parameters such as drilling depth, drilling diameter, hole–edge distance, and tension stress on the amount of stress release. Finally, through a homemade tensioning platform, we verify the reasonableness of the finite element simulation calculation law and determine coefficients A and B. The results of the study show that based on Kirsch’s analytical formula and the theory of microvia release, the axial tension force and axial strain are linearly correlated; the Midas FEA NX finite element software can effectively simulate the force state of strand cross-section; and through the strand-drilled hole model simulation and analysis, it is found that the tension stress value and the stress-release amount are related to the tensile stress value and the tensile stress value. We found that the value of tensile stress and the amount of stress released are positively correlated; with the increase in the hole margin, the amount of stress released gradually decreases; with the increase in the diameter of the hole, the amount of strain released gradually increases; and the greater the depth of the hole, the greater the amount of strain release. Moreover, the use of a hole margin of 3–6 mm, a hole diameter of 1.5 mm and 1.8 mm, and a hole depth of 2.5 mm is more reasonable in the test conditions, as follows. Through the drilling test conditions of 1.5 mm drilling diameter, 2.5 mm drilling depth, and 4 mm hole side distance, we verified the measured strain value of the steel wire and the tensile force value of the linear correlation between the functional relationship and the use of this functional relationship to determine the theoretical derivation of the coefficient to be determined: A is 1.12 and B is 57.84.

Effects of Nozzle Diameter and Holes Number on the Performance and Emissions of a Gasoline Direct Injection Engine

The goal of the current study is to estimate how a gasoline direct injection (GDI) engine's performance and emissions are affected by the fuel injector nozzle diameter and hole number of its injectors. A thermodynamic mathematical modelling has been created utilizing a software program written in the MATLAB language to simulate the two-zone combustion process of a four-stroke direct injection engine running on gasoline at (Rotation Engine Speed 3000 revolution per minute (rpm), 40 MPa injection pressure, compression ratio 9.5, and spark timing 145°). The first law of thermodynamics, equation of energy, mass conserving, equation of state, and mass fraction burned were all used in the creation of the software program. The study was carried out at five different nozzle diameters (0.250, 0.350, 0.450, 0.550, and 0.650 mm) and nozzle hole numbers (4,6,8,10,12). The results show that the GDI engine's performance and emissions are significantly influenced by variations in nozzle hole diameter and number. It was shown that engine power, heat transfer, cylinder pressure, and temperature increased with increasing nozzle hole diameter and number of nozzle holes and the maximum value was seen with nozzle hole diameter 0.650 mm and (12) holes. The lowest value for the nozzle hole diameter and number of holes was found to be 0.250 mm and 4 nozzle holes, which resulted in the lowest emissions of carbon monoxide CO and nitrogen monoxide NO. The study was also conducted for different operating conditions (Rotation Engine speed of 1000, 2000, 3000, 4000, 5000 rpm ,35 MPa injection pressure , compression ratio of 11.5 , and spark timing of 140° ) and the same nozzle diameters and nozzle holes number mentioned previously to estimate the maximum values for temperature, pressure, power , heat transfer and emissions . The results of the second part of the study showed that the highest of maximum values of temperature, pressure, and emissions were at of 1000 rpm, a nozzle diameter of 0.650 mm, and (12) holes. The highest values for maximum power at 4000 rpm, a nozzle diameter of 0.650 mm and (12) holes, while the highest maximum values for heat transfer are at 5000 rpm, a diameter of 0.65mm and (12) holes.