Direct Water Injection Research Articles

Water injection in directly injected turbocharged spark ignition engines

The paper explores the use of water injection in a turbocharged, direct injection, spark ignition engines fuelled with ethanol where port injection of water numerically prove to be effective in increasing the charge efficiency, reducing the tendency to knock, and controlling the temperature of gases to turbine. With injection of water in selected operating conditions, the engine may run higher compression ratios and boost pressures and closer to maximum brake torque spark advances for improved top power output and peak efficiency as well as better part load efficiencies. The paper suggests the introduction of this old technique now used in aftermarket kits possibly evolved to direct water injection in the design stage of novel turbocharged engines.

Evaluation of a low temperature fuel cell system for residential CHP

CHP (combined heat and power) is a technology that allows to provide electrical and thermal energy. CHP is normally used in systems that produce wasted heat at high temperature to recover energy and increase overall system efficiency. The aim of this work is to investigate the possibility to recover heat produced by a 5 kW PEFC system for residential applications (hot water and building heating). As known, PEFCs work at low temperature (60–90 °C) and the experiments have been carried out in order to improve the overall system efficiency by reusing heat that is normally wasted. The work was developed during an Italian National project PNR-FISR “Polymeric and Ceramic Fuel Cell” coordinated by CNR-ITAE. A 5 kW PEFC system, developed with NUVERA Fuel Cells in the framework of the project, was tested in cogeneration configuration recovering wasted heat with a heat exchanger directly connected to cathode out. Tests on PEFC system were carried out in the range 2.5–5 kW, maintaining the working stack temperature at 71 °C. Heat, produced at different power levels, was removed from the system by using a regulated water flow in the heat exchanger. A peculiar feature of the system is the so-called “direct water injection” at the cathode, that allows simultaneous cooling and humidification of the stack. This characteristic permitted the recovery of most of the waste heat produced by the fuel cell. The performance of the PEFC unit was analyzed in terms of electrical, thermal and total efficiency. Tests showed that it is possible to obtain water at about 68 °C under different power levels. Moreover, experimental data showed that heat recovered was maximum when heat exchanger worked at nominal power and, under these conditions, the overall system efficiency increased up to 85%.

水技術（水エマルジョン，水噴射，吸気加湿等）による NOx 低減技術

水技術（水エマルジョン，水噴射，吸気加湿等）による NOx 低減技術

Proton Exchange Membrane Fuel Cell Air Management in Automotive Applications

This paper deals with the state-of-the-art of air management in proton exchange membrane fuel cell (PEMFC), which is a challenge because commercial compressors and humidification systems are not suitable for automotive applications. Major tasks and requirements for compression and humidification subsystems have been introduced, showing that compression and humidification subsystems cannot be decoupled. A higher working pressure around 2.5 bar is recommended because it permits the PEMFC to have a higher efficiency, as well as a lighter stack and a lower volume than an equivalent PEMFC working at a lower pressure; moreover, the water necessary for humidifying the membrane decreases, resulting in a simple management. For high pressure fuel cells, centrifugal compressors or positive displacement compressors with internal compression have to be preferred than those with external compression because they offer a better efficiency. The built-in compression ratio has to be as close as possible to the fuel cell working pressure to ensure maximum efficiency. Downstream or integrated direct water injection has shown many advantages for air humidification compared with other methods because of its controllability, low power consumption, and compactness.

燃料液滴と水液滴の衝突を考慮した独立水噴射方式ディーゼル機関における噴霧挙動の数値予測- 第一報：油水衝突の有無と合体後の蒸発特性が噴霧に与える影響

Droplet collision in a diesel spray has been studied through observation of binary collision of two equivalent droplets of the same kind. In a direct water injection (DWI) system, a two-needle injector may produce considerable collisions between fuel and water droplets, and because of the near co-axial nozzle hole layout. In this study, the empirical criteria were directly adopted into KIVA3 code. This was divided into bounce, coalescence and separations after the collision of two droplets of any kind. The effective entrainment of water into fuel spray was numerically captured in the DWI system of the two-needle injector. The results were partially confirmed through observation of the actual DWI spray in a constant volume bomb.

F205 高断熱性2サイクルディーゼルエンジンの概念設計(OS3 バイオマス・新燃料・環境技術)

This Proposed new-type Opposite Pistons type 2Cycle Diesel engine has 4 features. 1) Exhaust port position and Scavenging port position are variable in a cycle to enlarge expansion volume so that Miller Cycle and High-Adiabatic combustion chamber ( double-Stroke/Boar=3) is available. 2) Premixed fuel injection at 20degBTDC and Pilot Torch Ignitor is able to high-load premixed combustion. 3) Adding After-burning fuel Injection at 12degATDC and Turbo-Compound increase power (MEP20bar). 4) Direct Water Injection into cylinder increase power and decrease NOx-emission. These features decrease Cooling Heat Loss by half and better thermal efficiency of this new-type engine to 55%.

Emissions from large-scale medium-speed diesel engines: 3. Influence of direct water injection and common rail

The influence of direct water injection (DWI) on emissions from a multivariable large-scale (6–18 cyl, ~ 1 MW/cyl) diesel engine is reported, using a combined injection valve and nozzle that allows for injection of water and fuel oil into the cylinder. This method allows for injecting a relatively large amount of water without derating the engine power and NO x emissions can be more than halved by DWI. Indeed DWI decreases combustion temperatures and NO x emissions, but it gives somewhat increased (yet not problematic) emissions of CO, HC, soot (smoke) and particulate matter (PM), depending on the water injection timing and degree of incomplete combustion. Common rail (CR) technology offers almost unlimited possibilities to control the fuel injection and to meet emission regulations. Different from a conventional injection system, the CR concept is based on the optimization of fuel pumping, injection timing, and injection rate. Optimum combustion is guaranteed by the CR engine map. For generator mode, CR resulted in clearly lower emissions of NO x , HC, CO and soot. Combining CR with DWI resulted in yet lower NO x (max. ca 50% reduction) and somewhat lower HC emissions but slightly higher CO and soot emissions.

Direct water injection in a medium speed gas engine

The optimization of gas engine combustion technology over the last 15 years has resulted in a astonishing reduction of fuel consumption. In the context of a project of the WTZ Roslau gGmbH the effects of a direct water injection were examined for the characteristic values and the operational behaviour of a single-cylinder research engine. Thereby characteristics of the 13.6-l SI gas engine for combined heat and power plants were from special interest such as NOx emission, efficiency, knocking behaviour and break mean effective pressure.

Combustion Characteristics Coupled with Direct Water lnjection through Double-Needle Type Injector

Direct water injection (DWI) seems to be a promising solution for NOx reductions from marine diesels thanks to its wide flexibility in water injection. Its true potential, however, remains uncertain because both numerical and experimental investigations are necessary to determine the best injection pattern, which can balance greater NOx reduction and less thermal efficiency loss especially for two-stroke diesel engines with peripheral injector location. In this study, a double-needle single-injector type DWI system was tested in a two-stroke engine with peripheral injector layout to evaluate its NOx reduction capability under the existence of swirling flow. Its effect on flame temperature was investigated experimentally by flame temperature measurement and numerically by CFD simulation. It was found that injected water affected fuel spray penetration and its air entrainment around spray tip. For tested engine configuration, it is found simultaneous fuel and water injection was most effective in reducing NOx emission.

Numerical Evaluation of a New Strategy of Emissions Reduction by Urea Direct Injection for Heavy Duty Diesel Engines

The effect of ammoniac deoxidizing agent (Urea) on the reduction of NOx produced in the Diesel engine was investigated numerically. Urea dissolved in water was directly injected into the engine cylinder during the expansion stroke. The NOx deoxidizing process was described using a simplified chemical kinetic model coupled with the comprehensive kinetics of Diesel oil surrogate combustion. If the technology of DWI (Direct Water Injection) with the later injection timing was used, the deoxidizing reactants could be delivered in a controlled amount directly into the flame plume zones, where NOx formed. Numerical simulations for the Isotta Fraschini DI Diesel engine were carried out using the KIVA-3V code, modified to account for the “co-fuel” injection and reaction with combustion products. The results showed that the amount of NOx could be substantially reduced up to 80% with the injection timing and the fraction of Urea in the solution optimized.

Liquid-Metal/Water Direct Contact Heat Exchange: Flow Visualization, Flow Stability, and Heat Transfer Using Real-Time X-Ray Imaging

Advanced reactor system designs are being considered with liquid-metal cooling connected to a steam power cycle. In addition, current reactor safety systems are considering auxiliary cooling schemes that assure ex-vessel debris coolability utilizing direct water injection into molten material pools to achieve core quenching and eventual coolability. The phenomenon common in both applications is direct contact heat exchange. The current study focuses on detailed measurements of liquid-metal/water direct contact heat exchange that is directly applicable to improvements in effective heat transfer in devices that are being considered for both of these purposes.In this study, a test facility was designed at the University of Wisconsin-Madison to map the operating range of liquid-metal/water direct contact heat exchange. The test section (184-cm height, 45.75-cm width, and 10-cm depth) is a rectangular slice of a larger heat exchange device. This apparatus was used not only to provide measurements of integral thermal performance (i.e., volumetric heat transfer coefficient), but also local heat transfer coefficients in a bubbly flow regime with X-ray imaging based on measured parameters such as bubble formation time, bubble rise velocity, and bubble diameters.To determine these local heat transfer coefficients, a complete methodology of the X-ray radiography for two-phase flow measurement has been developed. With this methodology, a high-energy X-ray imaging system is optimized for our heat exchange experiments. With this real-time, large-area, high-energy X-ray imaging system, the two-phase flow was quantitatively visualized. An efficient image processing strategy was developed by combining several optimal digital image-processing algorithms into a software computational tool written in MATLAB called T-XIP. Time-dependent heat transfer-related variables such as bubble volumes and velocities, were determined. Finally, an error analysis associated with these measurements has been given based on two independent procedures. This methodology will allow one to utilize X-ray attenuation for imaging vapor bubbles with acceptable errors (bubbles ~1 to 5 cm ± 5 to 20%).Subcooled water (Tsat – Twater [approximately equal to] 10°C) was brought into contact with liquid lead (or lead alloys) at an elevated temperature (Tlm = 500°C and Tlm – Tmelting [approximately equal to] 200°C). The study was conducted over a range of ambient pressures (1 to 10 bar) with four different water injection rates (1.5 to 8 g/s; 0.1 to 1 kg/m2·s). The results showed that the system pressure has a slight effect on volumetric heat transfer coefficient, the bubble formation time, and the bubble rise velocity. Increasing the system pressure, however, resulted in an increase in the bubble average heat transfer coefficient. Increasing the water injection rate directly had only a small effect on the bubble rise velocity or formation rate. Increasing the water injection rate resulted in a decrease in the local bubble heat transfer coefficient.Direct contact heat transfer also has some key disadvantages; e.g., flow instabilities caused by local vapor explosion is one of the issues related to direct contact heat exchange, particularly for liquid/liquid exchange with high temperature differences. In this study, the region of stable heat transfer was mapped and the effects of the liquid metal temperature, the water injection rate, and the operating pressure were investigated. The pressure required to stabilize the heat exchange process was found to be a function of the water injection rate but generally increasing the system pressure helped stabilize the system. It was also found that the larger the injection rate, the higher the pressure required to stabilize the system.

Occurrence of bacteria in industrial fluid power systems

Water hydraulic systems use water as a pressure medium to minimize the adverse environmental impacts of oil-using hydraulics. Microbial growth in the systems may restrict the applicability of this technology. In this work, occurrence of bacteria in three different full-scale water hydraulic applications operating in different industries was studied. Bacteria were found from different parts of diesel engine direct water injection (DWI) systems in the range of 1.8×105–1.0×107 cells/ml. Filters designed for removal of mechanical particles released bacteria and particles into the pressure medium indicating that a more frequent change of filters was needed or better filters for microbial control should be developed. The microbiological quality of the pressure medium in the DWI systems did not significantly change during the hydraulic circuit indicating suitability for long-term operation. The DWI studies showed that tap water quality is sufficient to ensure the long-term operation of full-scale water hydraulic applications. The microbiological quality of the pressure medium in a nuclear power plant remained stable (1.4–2.1×105 cells/ml) over long-term operation. The results confirmed that water hydraulics, with demineralized water as a pressure medium, can be used in such demanding applications as nuclear power plants. In the pressure medium of the hydraulic system of a wood processing plant, microbial growth resulted in malfunction. Bacteria should be controlled by a better quality pressure medium rather than the use of a biocide.

(1-02) Visual Study on Combustion of Low-Grade Fuel Water Emulsion((DE-1)Diesel Engine Combustion 1-Combustion and Emission Control)

In CIMAC in May 2001, the largest congress for marine and stationary engines in the world, many engine builders have announced that they apply the water injection into the cylinder to reduce the NOx emission. There are three methods of water injection into the cylinder, FWE (Fuel Water Emulsion), SFWI (Stratified Fuel Water Injection) and DWI (Direct Water Injection) [1]. At the last COMODIA in 1998, the authors presented about the effect of stratified fuel water injection to reduce NOx and smoke at the same time [2]. In the present study, to confirm the effect of fuel-water emulsion on combustion, experiments have been carried out using a visual engine and a visual combustion chamber. Figure 1 shows the burning flames in the two cases, (a) pure BFO (Bunker Fuel Oil) and (b) BFO-water emulsion. The combustion system of the visual engine simulates the one for low-speed marine engines. According to it, the flame of (b) shows the better combustion state, less soot-cloud and less after-burning than the flame of (a). In the presentation, reduction of the flame temperature measured by the two-color method and reduction of the soot formation inside the flame observed by the back diffused laser photo technique applying the fuel-water emulsion are introduced.

Effect of direct liquid water injection and interdigitated flow field on the performance of proton exchange membrane fuel cells

Proper water management is vital to ensuring successful performance of proton exchange membrane fuel cells. The effectiveness of the direct liquid water injection scheme and the interdigitated flow field design towards providing adequate gas humidification to maintain membrane optimal hydration and alleviating the mass transport limitations of the reactants and electrode flooding is investigated. It is found that the direct liquid water injection used in conjunction with the interdigitated flow fields as a humidification technique is an extremely effective method of water management. The forced flow-through-the-electrode characteristic of the interdigitated flow field (1) provides higher transport rates of reactant and products to and from the inner catalyst layers, (2) increases the hydration state and conductivity of the membrane by bringing its anode/membrane interface in direct contact with liquid water and (3) increases the cell tolerance limits for excess injected liquid water, which could be used to provide simultaneous evaporative cooling. Experimental results show substantial improvements in performance as a result of these improvements.

Large-volume PTV injection: Comparison of direct water injection and in-vial extraction for GC analysis of triazines

The potential of large-volume PTV injection was studied for the analysis of triazine herbicides in water samples. Direct water injection and in-vial extraction were described and compared. Detection limits were between 0.01–0.02 μg L−1 and relative standard deviations were <9%. Both methods are suitable for the analysis of triazines at ppt-level, although in-vial extraction is favourable for water samples with relatively large amounts of matrix components.

Water Mixing Combustion for Low NOx Diesel Engine. Direct Water Injection and Effects on Cylinder Lubrication.

A newly developed stratified fuel-water-injection system has been tested for NOx reduction, targeting the future strict restrictions to be set for slow-speed cross-head marine diesel engines. In addition to this system, we have developed anothor possible measure of a direct water injection system. We introduce the details of various test results in comparison to stratified fuel-water-injection system, and also discuss the expected effects on cylinder lubrication of the two different water-injection systems.

Determination of volatile halogenated hydrocarbons in tap water, seawater and industrial effluents by glass capillary gas chromatography and electron capture detection

AbstractA rapid and sensitive method to determine volatile organohalides in different types of waters has been developed. The chromatographic system is based on the resolving power of the glass capillary column and the high sensitivity of the electron capture detector. The capillary columns were connected to the detector so that the eluate from the column is mixed with thermostatted purge gas to minimize band broadening due to dead volumes. The low column bleeding and decreased band spreading from capillary columns enhance the sensitivity to very low levels: 1 fg (10−15g) for carbon tetrachloride, despite dilution of the column eluate by the purge gas.The water samples of 100 ml were extracted with 1 to 10 ml n‐pentane which is the most practical alkane with respect to purity. When using high water to pentane ratios corrections had to be made, due to low extraction yield, to get accurate quantifications.A column with Carbowax 400 stationary phase permits direct tap water injection. The water peak concealed the substances eluated after CHCl3 and CHBrCl2.The gas chromatographic separation of haloforms in tap water could be shortened to 30 seconds using a 10 m SE–52 column with an increased film thickness.Besides tap water and seawater, industrial waste water from a pulp mill was analyzed. Ten different halogenated organic compounds, ranging from 1 ng/I to 760 μg/I, were quantified in the different waters. Bromoform, which had not previously been found in seawater, was detected.Chromatogram of a standard mixture containing 11 organohalides. Stationary phase, SE‐52; 33 m × 0.3 mm i.d. inj. temp. 200°, column temp. 50°, interface 250°, detector temp. 250°. Helium carrier gas flow rate, 36 cm/s, scavenger'gas flow 30 ml/min.Split ratio 1:20, 1 = CH2CI2, 2 = CHC13, 3 = CH3CC13, 4 = CC14, 5 = CHCICCI2, 6 = CHBrCI2, 7 = CBrC13, 8 = CHBr2Cl, 9 = CCl2CC12, 10 = CHCl2l, 11 = CHBr3.

Direct water injection cooling for military engines and effects on the diesel cycle

A study was conducted on the feasibility of totally cooling a single-cylinder diesel engine by direct injection of water into the combustion chamber. The term “total cooling” can be taken to mean stabilized cooling at all loads and speeds so as to eliminate need for conventional cooling jackets, cooling fins, or oil spray jets. The engine used was a CLR Direct Injection Diesel with 42.5 cubic inch displacement and a compression ratio of 16:1. Most of the running was at 1800 rpm and 92 psi IMEP. Separate measurements were made of heat rejection to the cylinder head, liner, and crank-case oil to determine more accurately where the cooling effect was being applied. Water injection was by means of a Bosch pump and various pencil-type nozzles installed, adjacent to the fuel injector in the cylinder head. Port injection and port induction were also briefly investigated. A five-hole, 90° included angle nozzle was used, as was a three-hole, 30° included angle unit. For comparison, a nozzle directing one spray obliquely at the cylinder wall was also tested. Firing pressure was monitored using a piezo-electric transducer; both pressure-time and pressure-volume (indicator) records were obtained. In order to determine timing of both fuel and water injection, needle lift was monitored using a differential transformer pickup. The results of this study indicate: t Optimum total engine cooling by direct water injection was accomplished over a wide range of water injection timings (from 450 to 720 CA degrees after TDC power stroke) at water/fuel ratios of 2.9 to 3.7 with output power and brake specific fuel consumption improved 5 to 20%, respectively, over that with the standard jacket-cooled CLR engine. Emissions are affected in an expected manner by the presence of water: NO x is decreased, sometimes substantially, while the other emissions (HC, CO) tend to increase. When cooling the exhaust, the condensate becomes an effective scrubber of sulfur oxides. NO x was not significantly reduced by scrubbing, but if the condensate is made sufficiently alkaline (pH>8), CO 2 was unintentionally scrubbed out. The quality of the uncondensed exhaust for turbocharging is attractive. A theoretical gain of about 17.5% in available exhaust energy due to generation of steam was calculated, along with a temperature decrease of several hundred degrees Fahrenheit. Water contamination of the lubricating oil varies from negligible to extreme, depending on injection quantity, timing, and spray pattern. By not directing water at the liner wall, and by keeping the oil above 212°F, one can maintain the oil in a dry condition. Based on this work, several pertinent recommendations have been made: (1) utilize water injection for short-duration, very high-output operation which would otherwise be destructive due to thermal overload; (2) use water induction cooling in event of loss of conventional liquid coolant; (3) utilize exhaust scrubbing in stationary applications to permit burning of high-sulfur fuels without producing sulfur oxide emissions; nitrogen oxides could likewise be reduced by the injection of small amounts of water; and (4) since 2-stroke-cycle engines are an important category of diesel engines, some work similar to this effort should be done to this engine type; prospects are good for success, but conditions are apt to be more restrictive.

Time-temperature history in an underground cavity following rupture of a pressurized water nuclear reactor coolant system

Analysis shows that the pressure in the underground containment cavity of the S.E.N.A. Centrale Nucléaire des Ardennes following a hypothetical rupture of the primary coolant system can be safely controlled by a reasonable program of direct water injection, followed by a quenching overhead spray with cooling and recirculation of the spray water.