Theoretical Study on Similarity of Diesel Combustion

Li, Tie; Lai, Zheyuan; Wang, Bin

doi:10.4271/2018-01-0235

Cited by 12 publications

(13 citation statements)

References 33 publications

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“…They reported that the small engine has more heat transfer loss than the large engine with different test conditions. Since the effects of difference in the S/V ratio between different size engines can be to some extent compensated by the engine speed if the mean piston speed is equal, 18 the present authors 19 indicated that the P rule with the constant mean piston speed is better to scale the heat transfer loss.…”

Section: Introductionmentioning

confidence: 65%

“…This article is therefore aimed to study the similarity of spray characteristics with the split-injection strategies. First, the single value conditions for the three scaling rules derived in the previous study 1,19 are briefly described. Then, the similarity of spray characteristics including the spray tip and tail penetrations as well as averaged equivalence ratio is theoretically analyzed.…”

Section: Introductionmentioning

confidence: 99%

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Similarity of split-injected fuel sprays for different size diesel engines

Lai

Huang

2019

International Journal of Engine Research

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Establishment of a scaling relationship between small and large bore diesel engines is useful for saving energy, cost and time in a new engine development. Split-injection strategies, which are deemed effective to reduce simultaneously the engine noise and fuel consumption as well as soot and NOx emissions, have been commonly used in modern diesel engines. Thus, far knowledge about scaling the split-injected sprays is however still absent. In this article, the similarity of spray characteristics including the spray tip and tail penetrations as well as the averaged equivalence ratio is theoretically analyzed. With two nozzles of 0.11 and 0.14 mm hole diameters, the similarity of fuel injection rate and non-evaporating spray mixture formation processes with the main-post and pilot-main injection strategies is studied for the three scaling rules, via the Bosch long tube method and high-speed shadowgraphy, respectively. The experimental results agree well with the theoretical analyses. All the three scaling rules can scale the injection rate and injection mass very well with the split-injection strategies under the varied injection pressures. The pressure rule is better to scale the spray tip and tail penetrations, while the lift-off rule and speed rule lead to relatively longer spray tip and tail penetration lengths. The spray lengths of the small-type nozzles with the lift-off rule and speed rule are longer than those of the small-type nozzle with the pressure rule and the large-type nozzle, resulting in a decreased averaged equivalence ratio for the former cases. These results are valuable for evaluating the scaling rules for different size diesel engines with a wide range of operation conditions and guiding new diesel engine development.

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Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Similarity of split-injected fuel sprays for different size diesel engines

Lai

Huang

2019

International Journal of Engine Research

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“…The increased liquid length of the small engines will increase the likelihood of the wall impingement, which is one reason for the increased soot emissions of the small engines. 45 Generally, the maximum liquid penetration length can be well scaled for all three scaling laws, especially for the P law.…”

Section: Resultsmentioning

confidence: 99%

“…The single value conditions for the similarity of diesel combustion are summarized in Figure 1, for more detailed information, consult previous studies. 6,45…”

Section: Single Value Conditionsmentioning

confidence: 99%

“…The purposes of this article are therefore to investigate the similarity of liquid penetration in evaporating fuel sprays and clarify the evaporation mechanism of high-pressure diesel spray. First, a brief description of the single value conditions summarized in the previous studies 6,45 is given. Then, the similarity of maximum liquid penetration length is derived based on the hypotheses that the spray evaporation processes are fuel–air mixing controlled and local interphase transport controlled, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Scaling liquid penetration in evaporating sprays for different size diesel engines

Wei

Wang

2019

International Journal of Engine Research

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Scaled model experiments can greatly reduce the cost, time and energy consumption in diesel engine development, and the similarity of spray characteristics has a primary effect on the overall scaling results of engine performance and pollutant emissions. However, although so far the similarity of spray characteristics under the non-evaporating condition has been studied to some extent, researches on scaling the evaporating sprays are still absent. The maximum liquid penetration length has a close relationship with the spray evaporation processes and is a key parameter in the design of diesel engine spray combustion system. In this article, the similarity of maximum liquid penetration length is theoretically derived based on the hypotheses that the spray evaporation processes in modern high-pressure common rail diesel engines are fuel–air mixing controlled and local interphase transport controlled, respectively. After verifying that the fuel injection rates are perfectly scaled, the similarity of maximum liquid penetration length in evaporating sprays is studied for three scaling laws using two nozzles with hole diameter of 0.11 and 0.14 mm through the high-speed diffused back-illumination method. Under the test conditions of different fuel injection pressures, ambient temperatures and densities, the lift-off law and speed law lead to a slightly increased maximum liquid penetration length, while the pressure law can well scale the maximum liquid penetration length. The experimental results are consistent with the theoretical analyses based on the hypothesis that the spray evaporation processes are fuel–air mixing controlled, indicating that the local interphase transports of energy, momentum and mass on droplet surface are not rate-controlled steps with respect to spray evaporation processes.

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Scaling the turbulent jet by active pre-chamber

Wu,

Zhou,

et al. 2024

Applied Thermal Engineering

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Theoretical Study on Similarity of Diesel Combustion

Cited by 12 publications

References 33 publications

Similarity of split-injected fuel sprays for different size diesel engines

Similarity of split-injected fuel sprays for different size diesel engines

Scaling liquid penetration in evaporating sprays for different size diesel engines

Scaling the turbulent jet by active pre-chamber

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