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NACA-RM-E54F11
Experimental heat-transfer and friction coefficients for air flowing through stacks of parallel flat plates
Year: 1954
Abstract: INTRODUCTION
The present investigation was undertaken to obtain forced-convection heat-transfer and pressure-drop data for flow of air between electrically heated parallel flat plates forming passages of short length-to-effective-diameter ratio. More specifically, the program was designed to provide these data for successive stacks of plates, wherein the effects of such configuration variables as distance between parallel plates, gap spacing between successive stacks, and degree of misalinement between plates in successive stacks are to be evaluated for a range of Reynolds numbers, plate surface temperatures, and heat fluxes.
These data are of interest in the design of heat exchange similar geometries (and plain or interrupted surfaces), where advantage can be taken of the increased-heat transfer associated with flow in passages of short length-diameter ratio. In addition t o average heat-transfer values, the design of heat exchangers may require a more detailed knowledge of local surface-temperature gradients or limiting local temperatures, in which case recourse must be made to local heat-transfer values. Both local and average heat-transfer coefficients are reported herein.
In the present investigation, heat-transfer and pressure-drop data were obtained for two stacks of parallel flat plates with a 1/4 –inch spacing between plates in each stack, various degrees of plate misalinement, and various gap spacings (1/32, 1/8, and 1/4 in.) between stacks, as well as with the upstream stack removed. The data reported herein were obtained with heat addition to the downstream stack only. Data were obtained over a range of Reynolds numbers from 15,000 to 80,000, average surface temperatures from 661° to 683° R, heat fluxes up to 8080 Btu per hour per square foot, an inlet air temperature of about 518° R, and inlet pressures up to 45 inches of mercury absolute.
The results are presented herein in the form of curves of average values of a Nusselt-Prandtl number relation (Nu/Pr0.4) against Reynolds number, of local heat-transfer coefficients and plate temperatures against distance from leading edge of plate, and of average friction factors against Reynolds number.
The present investigation was undertaken to obtain forced-convection heat-transfer and pressure-drop data for flow of air between electrically heated parallel flat plates forming passages of short length-to-effective-diameter ratio. More specifically, the program was designed to provide these data for successive stacks of plates, wherein the effects of such configuration variables as distance between parallel plates, gap spacing between successive stacks, and degree of misalinement between plates in successive stacks are to be evaluated for a range of Reynolds numbers, plate surface temperatures, and heat fluxes.
These data are of interest in the design of heat exchange similar geometries (and plain or interrupted surfaces), where advantage can be taken of the increased-heat transfer associated with flow in passages of short length-diameter ratio. In addition t o average heat-transfer values, the design of heat exchangers may require a more detailed knowledge of local surface-temperature gradients or limiting local temperatures, in which case recourse must be made to local heat-transfer values. Both local and average heat-transfer coefficients are reported herein.
In the present investigation, heat-transfer and pressure-drop data were obtained for two stacks of parallel flat plates with a 1/4 –inch spacing between plates in each stack, various degrees of plate misalinement, and various gap spacings (1/32, 1/8, and 1/4 in.) between stacks, as well as with the upstream stack removed. The data reported herein were obtained with heat addition to the downstream stack only. Data were obtained over a range of Reynolds numbers from 15,000 to 80,000, average surface temperatures from 661° to 683° R, heat fluxes up to 8080 Btu per hour per square foot, an inlet air temperature of about 518° R, and inlet pressures up to 45 inches of mercury absolute.
The results are presented herein in the form of curves of average values of a Nusselt-Prandtl number relation (Nu/Pr0.4) against Reynolds number, of local heat-transfer coefficients and plate temperatures against distance from leading edge of plate, and of average friction factors against Reynolds number.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T16:49:36Z | |
| date available | 2017-09-04T16:49:36Z | |
| date copyright | 01/01/1954 | |
| date issued | 1954 | |
| identifier other | WLMCWDAAAAAAAAAA.pdf | |
| identifier uri | https://yse.yabesh.ir/std/handle/yse/113115 | |
| description abstract | INTRODUCTION The present investigation was undertaken to obtain forced-convection heat-transfer and pressure-drop data for flow of air between electrically heated parallel flat plates forming passages of short length-to-effective-diameter ratio. More specifically, the program was designed to provide these data for successive stacks of plates, wherein the effects of such configuration variables as distance between parallel plates, gap spacing between successive stacks, and degree of misalinement between plates in successive stacks are to be evaluated for a range of Reynolds numbers, plate surface temperatures, and heat fluxes. These data are of interest in the design of heat exchange similar geometries (and plain or interrupted surfaces), where advantage can be taken of the increased-heat transfer associated with flow in passages of short length-diameter ratio. In addition t o average heat-transfer values, the design of heat exchangers may require a more detailed knowledge of local surface-temperature gradients or limiting local temperatures, in which case recourse must be made to local heat-transfer values. Both local and average heat-transfer coefficients are reported herein. In the present investigation, heat-transfer and pressure-drop data were obtained for two stacks of parallel flat plates with a 1/4 –inch spacing between plates in each stack, various degrees of plate misalinement, and various gap spacings (1/32, 1/8, and 1/4 in.) between stacks, as well as with the upstream stack removed. The data reported herein were obtained with heat addition to the downstream stack only. Data were obtained over a range of Reynolds numbers from 15,000 to 80,000, average surface temperatures from 661° to 683° R, heat fluxes up to 8080 Btu per hour per square foot, an inlet air temperature of about 518° R, and inlet pressures up to 45 inches of mercury absolute. The results are presented herein in the form of curves of average values of a Nusselt-Prandtl number relation (Nu/Pr0.4) against Reynolds number, of local heat-transfer coefficients and plate temperatures against distance from leading edge of plate, and of average friction factors against Reynolds number. | |
| language | English | |
| title | NACA-RM-E54F11 | num |
| title | Experimental heat-transfer and friction coefficients for air flowing through stacks of parallel flat plates | en |
| type | standard | |
| page | 35 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1954 | |
| contenttype | fulltext |