The flow maldistribution and the effect of different inlet configuration on the flow distribution in platefin heat exchangers were studied experimentally. It is found that the flow maldistribution is serious because o...The flow maldistribution and the effect of different inlet configuration on the flow distribution in platefin heat exchangers were studied experimentally. It is found that the flow maldistribution is serious because of the defects of inlet configurations, while the inlet configuration and Reynolds number are the main factors affecting the flow distribution. The improved inlet configurations, which are the header with a two-stage distributing configuration and the guide vane with a fluid complementary cavity were proposed and tested in this paper. The experimental results show that the improved inlet configurations can effectively improve the performance of flow distribution in heat exchangers.展开更多
This paper investigates the effect of intake port configuration on the swirl that is generated within a direct injection(D.I.) diesel engine. The in-cylinder flow characteristics are known to have significant effects ...This paper investigates the effect of intake port configuration on the swirl that is generated within a direct injection(D.I.) diesel engine. The in-cylinder flow characteristics are known to have significant effects on fuel-air mixing, combustion, and emissions. To clarify how to intensify the swirl flow, a swirl control valve(SCV) and a bypass were selected as design parameters for enhancing the swirl flow. The optimal intake port shape was also chosen as a parameter needed to efficiently generate a high swirl ratio. The results revealed that a key factor in generating a high swirl ratio was to control the intake airflow direction passing through the intake valve seat. Further, the swirl intensity was influenced by changing the distance between the helical and tangential ports, and the swirl flow was changed by the presence of a bypass near the intake valve seat. Additionally, the effect of intake port geometry on the in-cylinder flow field was investigated by using a laser sheet visualization method. The experimental results showed a correlation of swirl ratio and mass flow rate. In addition, we found that employing the bypass was an effective method to increase swirl ratio without sacrificing mass flow rate.展开更多
基金Supported by the Doctoral Foundation of Xi'an Jiaotong University (No. DFXJTU2002-12) the Foundation for Excellent Doctoral Dissertation Author by Minister of Education, China (No. 199933).
文摘The flow maldistribution and the effect of different inlet configuration on the flow distribution in platefin heat exchangers were studied experimentally. It is found that the flow maldistribution is serious because of the defects of inlet configurations, while the inlet configuration and Reynolds number are the main factors affecting the flow distribution. The improved inlet configurations, which are the header with a two-stage distributing configuration and the guide vane with a fluid complementary cavity were proposed and tested in this paper. The experimental results show that the improved inlet configurations can effectively improve the performance of flow distribution in heat exchangers.
基金supported by the research fund of Hanyang University(HY-2012-P)
文摘This paper investigates the effect of intake port configuration on the swirl that is generated within a direct injection(D.I.) diesel engine. The in-cylinder flow characteristics are known to have significant effects on fuel-air mixing, combustion, and emissions. To clarify how to intensify the swirl flow, a swirl control valve(SCV) and a bypass were selected as design parameters for enhancing the swirl flow. The optimal intake port shape was also chosen as a parameter needed to efficiently generate a high swirl ratio. The results revealed that a key factor in generating a high swirl ratio was to control the intake airflow direction passing through the intake valve seat. Further, the swirl intensity was influenced by changing the distance between the helical and tangential ports, and the swirl flow was changed by the presence of a bypass near the intake valve seat. Additionally, the effect of intake port geometry on the in-cylinder flow field was investigated by using a laser sheet visualization method. The experimental results showed a correlation of swirl ratio and mass flow rate. In addition, we found that employing the bypass was an effective method to increase swirl ratio without sacrificing mass flow rate.
