• Title/Summary/Keyword: impingement angle

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An Experimental Studies on Impingement Spray Characteristic in High Temperature and Pressure Chamber (고온고압용기에서 충돌분무 특성에 관한 실험적 연구)

  • 안병규;류호성;오은탁;송규근;정재연
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.36-43
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    • 2002
  • The characteristics of spray has much effect on performance and emissions for automobile, diesel engine, gas turbine and combustion engines. So spray behavior after impinging the wall is very important for prediction the engine performance. This studies examined about impingement spray considering ambient density(18,24,30kg/ms), temperature(293,473K), impingement angle(0,30,45°). The images of impingement spray were obtained by the high speed video camera. After that we analyzed impingement spray characteristics to use this images. In this experiment, we found that 1) The spray width is reduced by increasing the ambient gas density and temperature,2) The growth of downstream is increased by increasing the impingement angle.

A study on the characteristics of gasoline spray to impinge on wall (벽면에 충돌하는 가솔린 분무의 특성에 관한 연구)

  • Lee, G.Y.
    • Journal of ILASS-Korea
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    • v.10 no.1
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    • pp.17-23
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    • 2005
  • Even though a relatively complete knowledge base has been established for diesel sprays, much of the knowledge cannot be directly translated to correlate the characteristics of gasoline spray. The macroscopic characteristics of gasoline impingement spray was investigated with photographic and image processing technique by Particle Motion Analysis System. The injector with single hole nozzle diameter of 0.28 mm was used in this experiment and the injection duration was selected as 10 msec. The injection pressure with 0.3, 0.35, and 0.4 MPa, impingement distance or 70, 100 and 130m, impingement angle or 0.15, 30 and $45^{\circ}$ were employed for the variables to affect the spray characteristics of impinging spray. It is clear that there is the analogy on the spray tip penetration between the gasoline impinging jet and diesel free jet. The spray tip penetration of impinging gasoline spray is proportional to the quarter power of the time after start of injection. The maximum height of impinging gasoline spray is also proportional to the quarter power of the time regardless of impingement distance, impingement angle and injection pressure. In addition, the effect of impingement angle on the spray tip penetration is significant according to the time after start of injection, even though there is minor effect in the initial stage of time after start of injection. Moreover, there is no remarkable effect of injection pressure on the spray tip Penetration under the experimental condition used in this study.

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Atomization Characteristics by Impigement of Spray (분무 상호 충돌에 의한 미립화 특성)

  • Kim, Chun-Jung;SAITO, Masahiro;ARAI, Masataka
    • Journal of the Korean Society of Industry Convergence
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    • v.1 no.2
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    • pp.41-48
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    • 1998
  • This experimental study describes atomization characteristics of spray-spray impingement. Effect of the impingement location and angle on the penetration and the sauter mean diameter of the impinged spray were investigated. Experiment were performed under ranging from 50kPa to 250kPa spray pressure, ranging $30^{\circ}C$ to $135^{\circ}C$ angle on the penetration and free spray. In the case of this experimental, sauter mean diameter $D_{32}$ tends to decrease and duration of film disintegration $t_f$ to decrease, when spray pressure and angle on the penetration is increased. Sauter mean diameter $D_{32}$ were about 20% to be smaller compared with a free spray to jet-jet impingement and 30% to be smaller compared with a free spray to spray-spray impingement.

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Spray Characteristics on Impingement Angle Variation and Mixture ratio of Impinging Injectors (충돌각과 혼합비 변화에 따른 충돌형 분사기의 분무특성에 관한 연구)

  • Gang, Sin Jae;Song, Beom Geun;Song, Gi Jeong;Lee, Jeong Gyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.5
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    • pp.72-79
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    • 2003
  • Spray characteristics were investigated by impinging F-O-O-F type injector with varying the impingement angle through 15, 20 and 30 degree and the mixture ratio(O/F ratio) from 1.5 to 3.0. Experimental results show that the correlation between dispersion and impingement angle is not influenced of the mixture ratio variation, but which has influence on number density, and there is a linear correlation between dispersion and impingement angle. Velocity distribution, standard deviation and SMD of droplets are decreased as the impingement angle increases. Also, it was confirmed that the distribution of droplet size are in accordance with Rosin-Rammler and Upper-limit distribution.

CHARACTERISTICS OF WALL IMPINGEMENT AT ELEVATED TEMPERATURE CONDITIONS ON GDI SPRAY

  • Park, J.;Im, K.S.;Kim, H.;Lai, M.C.
    • International Journal of Automotive Technology
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    • v.5 no.3
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    • pp.155-164
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    • 2004
  • The direct injection gasoline spray-wall interaction was characterized inside a heated pressurized chamber using various visualization techniques, including high-speed laser-sheet macroscopic and microscopic movies up to 25,000 frames per second, shadowgraph, and double-spark particle image velocimetry. Two hollow cone high-pressure swirl injectors having different cone angles were used to inject gasoline onto a heated plate at two different impingement angles. Based on the visualization results, the overall transient spray impingement structure, fuel film formation, and preliminary droplet size and velocity were analyzed. The results show that upward spray vortex inside the spray is more obvious at elevated temperature condition, particularly for the wide-cone-angle injector, due to the vaporization of small droplets and decreased air density. Film build-up on the surface is clearly observed at both ambient and elevated temperature, especially for narrow cone spray. Vapor phase appears at both ambient and elevated temperature conditions, particularly in the toroidal vortex and impingement plume. More rapid impingement and faster horizontal spread after impingement are observed for elevated temperature conditions. Droplet rebounding and film break-up are clearly observed. Post-impingement droplets are significantly smaller than pre-impingement droplets with a more horizontal velocity component regardless of the wall temperature and impingement angle condition.

An Experimental Investigation of Particle Impingement Erosion in Hydraulic Systems (유압시스템의 입자 침해 침식의 실험적 고찰)

  • 이재천;김성훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.117-122
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    • 2002
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop complete analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

An Experimental Investigation of Particle Impingement Erosion in Hydraulic System (유압시스템의 입자 침해 침식의 실험적 고찰)

  • 이재천
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.15-21
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    • 2001
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

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A Study on the Velocity Characteristics of the Spray Formed by Two Impinging Jets (충돌 제트로 형성되는 분무의 속도 특성에 대한 연구)

  • Choo, Yeon-Jun;Seo, Kwi-Hyun;Kang, Bo-Seon
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.87-93
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    • 2001
  • In this study, the velocity characteristics of liquid elements formed by two impinging jets is analysed using double pulse image capturing technique. For the droplets formed by low speed impinging jets, the droplet velocities are higher with smaller azimuthal and impingement angle. The maximum droplet velocities are about 25 % lower than jet velocity. With an increase of azimuthal angle, the shedding angles increases but remains lower than azimuthal angle. The velocities of ligaments formed by high speed impinging jets gradually decreases with an increase of azimuthal angle. The maximum ligament velocities are about 40 % lower than jet velocity. Higher impingement angles produce lower ligament velocities. The shedding angles of ligament almost increases with the same value of azimuthal angle, which implies that the moving direction of ligaments is radial from the origin as the impingement point.

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A Study on the Velocity Characteristics of the Spray Formed by Two Impinging Jets (충돌 제트로 형성되는 분무의 속도 특성에 대한 연구)

  • Choo, Yeon-Jun;Oh, Dai-Jin;Kang, Bo-Seon
    • Journal of ILASS-Korea
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    • v.6 no.2
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    • pp.1-8
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    • 2001
  • In this study, the velocity characteristics of liquid elements formed by two impinging jets is analysed using double pulse image capturing technique. For the droplets formed by low speed impinging jets, the droplet velocities are higher with smaller azimuthal and impingement angle. The maximum droplet velocities are about 25 % lower than jet velocity. With an increase of azimuthal angle, the shedding angles increases but remains lower than azimuthal angle. The velocities of ligaments formed by high speed impinging jets gradually decreases with an increase of azimuthal angle. The maximum ligament velocities are about 40% lower than jet velocity. Higher impingement angles produce lower ligament velocities. The shedding angles of ligament almost increases with the same value of azimuthal angle, which implies that the moving direction of ligaments is radial from the origin as the impingement point.

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Accessory Talar Facet Impingement due to Accessory Anterolateral Talar Facet Misdiagnosed as Sinus Tarsi Syndrome (족근동 증후군으로 오인된 Accessory Anterolateral Talar Facet에 의한 거종관절 충돌)

  • Park, Jae Woo;Park, Chul Hyun
    • Journal of Korean Foot and Ankle Society
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    • v.22 no.1
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    • pp.16-20
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    • 2018
  • Purpose: To evaluate the clinical and radiographic results of surgical treatment for patients with sinus tarsi pain due to accessory talar facet impingement. Materials and Methods: Between July 2013 and July 2015, nine patients who underwent surgery for the accessory talar facet impingement were reviewed. The mean follow-up period was 18.6 months (12~36 months), and the mean age was 33.1 years (19~60 years). Previous trauma history, duration of symptom, and types of surgery were analyzed. The clinical results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and visual analogue scale (VAS). Radiographic results were assessed using Meary's angle, calcaneal pitch angle, heel alignment angle, and heel alignment ratio. Results: All patients had evident trauma history prior to the initial symptom. The mean duration of symptoms was 25.6 months (6~120 months). Four patients received only accessory anterolateral talar facet (AALTF) excision, and four patients received medial sliding calcaneal osteotomy (MSCO). One patient underwent both AALTF excision and MSCO. The AOFAS ankle-hindfoot score was significantly improved from 73 (62~77) preoperatively to 93 (67~100) postoperatively. The VAS score was decreased from 6 (5~7) preoperatively to 1 (0~5) postoperatively. The Meary's angle and calcaneal pitch angle showed no significant difference after surgery. The heel alignment angle and ratio increased from $-3.6^{\circ}$ ($-10^{\circ}{\sim}5^{\circ}$) and 0.22 (-0.15~0.6) preoperatively to $2.8^{\circ}$ ($1^{\circ}{\sim}5^{\circ}$) and 0.42 (0.3~0.6) postoperatively, respectively. Conclusion: If there is persistent sinus tarsi pain in patients with hindfoot valgus, accessory talar facet impingement caused by AALTF could be considered as a cause of chronic sinus tarsi pain.