The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform

A Siami - One of the best experts on this subject based on the ideXlab platform.

A Najafi - One of the best experts on this subject based on the ideXlab platform.

M Asayesh - One of the best experts on this subject based on the ideXlab platform.

Zia Abdullah - One of the best experts on this subject based on the ideXlab platform.

  • Fluid-Elastic Instability in a Tube Array Subjected to Uniform and Jet Flow
    Journal of Pressure Vessel Technology-transactions of The Asme, 2004
    Co-Authors: P.a. Feenstra, David S. Weaver, Zia Abdullah
    Abstract:

    A wind tunnel study was carried out to investigate the fluidelastic stability of a model heat exchanger tube array subjected to a uniform cross-flow of air and a concentrated jet flow of air directed down a tube lane. The latter experiments were intended to simulate the effects of a Soot blower on the dynamic response of tubes which had apparently been the cause of catastrophic tube failure in a heat exchanger. The experimental results showed that the model tube array experienced fluidelastic instability when subjected to a uniform cross-flow beyond a dimensionless pitch flow velocity which was substantially above the maximum design flow velocity of the heat exchanger. These experiments established that normal operating conditions could not have been responsible for the tube failures. Additional experiments showed that a continuously translating nozzle dispensing a jet of air at the tubes caused some static deflection of the tubes but no serious vibrations were observed. However, when the nozzle was fixed at one location, whereby the jet of air issued directly down a tube lane, fluidelastic instability occurred in the first few tube rows. A simplified analysis showed that the jet could cause fluidelastic instability. It can be inferred that, for heat exchangers equipped with steam Soot Blowers, normal Soot blower operation should not cause fluidelastic instability but that a parked Soot blower can cause fatigue failure of the tubes adjacent to the impinging jet in a relatively short period of time.

  • Fluidelastic Instability in a Tube Array Subjected to Uniform Flow and Jet Flow
    Flow-Induced Vibration, 2003
    Co-Authors: P.a. Feenstra, David S. Weaver, Zia Abdullah
    Abstract:

    A wind tunnel study was carried out to investigate the fluidelastic stability of a model heat exchanger tube array subjected to a uniform cross-flow of air and a concentrated jet flow of air down a tube lane. The latter experiments were intended to simulate the effects of a Soot blower on the dynamic response of the tubes which had apparently been the cause of catastrophic tube failure in a heat exchanger. The experimental results showed that the model tube array experienced fluidelastic instability when subjected to a uniform cross-flow beyond a dimensionless pitch flow velocity of 24.4. For a mass damping parameter of 14.5, the Connors’ constant for this array is K = 6.4 which is over 2-1/2 times that of the conservative guideline of K = 2.4 recommended by the ASME boiler and pressure vessel code. These experiments established that the normal operating conditions of the heat exchanger should not lead to excessive tube vibration. It was shown that a continuously translating nozzle dispensing a jet of air at the tubes caused some static deflection of the tubes but no serious vibrations were observed that would be of concern from the standpoint of tube damage. However, when the nozzle was fixed at one location whereby the jet of air issued directly down a tube lane, fluidelastic instability occurred in the tubes in the first few rows, but some time was required for large amplitude vibrations to develop. It can be inferred that, for heat exchangers equipped with steam Soot Blowers, normal Soot blower operation should not cause fluidelastic instability but that a parked Soot blower can be expected to cause fatigue failure of the tube adjacent to the impinging jet in a relatively short period of time.Copyright © 2003 by ASME

P.a. Feenstra - One of the best experts on this subject based on the ideXlab platform.

  • Fluid-Elastic Instability in a Tube Array Subjected to Uniform and Jet Flow
    Journal of Pressure Vessel Technology-transactions of The Asme, 2004
    Co-Authors: P.a. Feenstra, David S. Weaver, Zia Abdullah
    Abstract:

    A wind tunnel study was carried out to investigate the fluidelastic stability of a model heat exchanger tube array subjected to a uniform cross-flow of air and a concentrated jet flow of air directed down a tube lane. The latter experiments were intended to simulate the effects of a Soot blower on the dynamic response of tubes which had apparently been the cause of catastrophic tube failure in a heat exchanger. The experimental results showed that the model tube array experienced fluidelastic instability when subjected to a uniform cross-flow beyond a dimensionless pitch flow velocity which was substantially above the maximum design flow velocity of the heat exchanger. These experiments established that normal operating conditions could not have been responsible for the tube failures. Additional experiments showed that a continuously translating nozzle dispensing a jet of air at the tubes caused some static deflection of the tubes but no serious vibrations were observed. However, when the nozzle was fixed at one location, whereby the jet of air issued directly down a tube lane, fluidelastic instability occurred in the first few tube rows. A simplified analysis showed that the jet could cause fluidelastic instability. It can be inferred that, for heat exchangers equipped with steam Soot Blowers, normal Soot blower operation should not cause fluidelastic instability but that a parked Soot blower can cause fatigue failure of the tubes adjacent to the impinging jet in a relatively short period of time.

  • Fluidelastic Instability in a Tube Array Subjected to Uniform Flow and Jet Flow
    Flow-Induced Vibration, 2003
    Co-Authors: P.a. Feenstra, David S. Weaver, Zia Abdullah
    Abstract:

    A wind tunnel study was carried out to investigate the fluidelastic stability of a model heat exchanger tube array subjected to a uniform cross-flow of air and a concentrated jet flow of air down a tube lane. The latter experiments were intended to simulate the effects of a Soot blower on the dynamic response of the tubes which had apparently been the cause of catastrophic tube failure in a heat exchanger. The experimental results showed that the model tube array experienced fluidelastic instability when subjected to a uniform cross-flow beyond a dimensionless pitch flow velocity of 24.4. For a mass damping parameter of 14.5, the Connors’ constant for this array is K = 6.4 which is over 2-1/2 times that of the conservative guideline of K = 2.4 recommended by the ASME boiler and pressure vessel code. These experiments established that the normal operating conditions of the heat exchanger should not lead to excessive tube vibration. It was shown that a continuously translating nozzle dispensing a jet of air at the tubes caused some static deflection of the tubes but no serious vibrations were observed that would be of concern from the standpoint of tube damage. However, when the nozzle was fixed at one location whereby the jet of air issued directly down a tube lane, fluidelastic instability occurred in the tubes in the first few rows, but some time was required for large amplitude vibrations to develop. It can be inferred that, for heat exchangers equipped with steam Soot Blowers, normal Soot blower operation should not cause fluidelastic instability but that a parked Soot blower can be expected to cause fatigue failure of the tube adjacent to the impinging jet in a relatively short period of time.Copyright © 2003 by ASME