{"id":403656,"date":"2025-01-06T05:34:28","date_gmt":"2025-01-06T05:34:28","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/calculating-flow-rate-and-pressure-fluctuations-for-filling-air-tanks\/"},"modified":"2025-01-06T05:34:28","modified_gmt":"2025-01-06T05:34:28","slug":"calculating-flow-rate-and-pressure-fluctuations-for-filling-air-tanks","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/calculating-flow-rate-and-pressure-fluctuations-for-filling-air-tanks\/","title":{"rendered":"Calculating Flow Rate and Pressure Fluctuations for Filling Air Tanks"},"content":{"rendered":"<p>&lt;p&gt;Hello everyone,&lt;\/p&gt;&lt;p&gt;I have a system with two air tanks, and a constant flow source providing air at 36 psi pressure. My goal is to calculate how the flow rate from the source will change as I fill the tanks. Initially, Tank 1 has 9 psi and Tank 2 has 16 psi. As air enters the tanks, due to the pressure buildup inside, the flow rate will be directed more towards the tank with the lower pressure, causing fluctuations in the flow rate from the source.&lt;\/p&gt;&lt;p&gt;Once the tanks reach the target pressure of 36 psi, the flow to both tanks will stop. I need to determine the following:&lt;\/p&gt;<\/p>\n<ol>\n<li>The time it will take to fill the tanks to 36 psi.<\/li>\n<li>How the flow rate will fluctuate during the process due to the pressure differences between the tanks.<\/li>\n<li>As the tanks are filled, the lower pressure tank (starting at 9 psi) will eventually catch up to the higher pressure tank (starting at 16 psi). I would like to see the pressure at which the two tanks will equalize, and what is the time it will take for this to happen.<\/li>\n<\/ol>\n<p>&lt;p&gt;Could someone help me understand how I can model and calculate these flow rate fluctuations and filling times? Also if I assume both tanks are empty initially, how should I set-up my simulation? Should I use multiphase flow and initially set tanks empty?&lt;\/p&gt;&lt;p&gt;&nbsp;&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/06-01-2025-1736141265-mceclip0.png\" \/>&lt;\/p&gt;&lt;p&gt;Thanks in advance!&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-403656","topic","type-topic","status-publish","hentry","topic-tag-fluent-cfd-ansys-1","topic-tag-compressible-flow-air-2"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"Hello everyone,I have a system with two air tanks, and a constant flow source providing air at 36 psi pressure. My goal is to calculate how the flow rate from the source will change as I fill the tanks. Initially, Tank 1 has 9 psi and Tank 2 has 16 psi. As air enters the\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/calculating-flow-rate-and-pressure-fluctuations-for-filling-air-tanks\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Calculating Flow Rate and Pressure Fluctuations for Filling Air Tanks | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"Hello everyone,I have a system with two air tanks, and a constant flow source providing air at 36 psi pressure. My goal is to calculate how the flow rate from the source will change as I fill the tanks. Initially, Tank 1 has 9 psi and Tank 2 has 16 psi. 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