{"id":{"repo_id":"wichita-thes","oai_identifier":"oai:soar.wichita.edu:10057/11599"},"canonical_url":"https://search.dev.ndltd.org/etd/wichita-thes/oai:soar.wichita.edu:10057/11599","repository":{"repo_id":"wichita-thes","name":"Wichita State University","base_url":"https://soar.wichita.edu/oai/request"},"display":{"title":"Numerical analysis of blood flow in an aortocoronary bypass model","abstract":"Aortocoronary bypass (ACB) surgery is a treatment to bypass a blocked artery using a graft. Approximately 500,000 bypass surgeries are performed in the U.S. each year. Of these, about 15% to 20% have an early-phase failure, typically in the proximal region. A natural question which arises is whether fluid dynamic geometry plays a role in the patency. Since only a few studies have considered proximal region geometry, this motivates the present study. Blood flow in a coronary artery bypass often involves very complex fluid dynamic behavior. Numerical simulation is employed to investigate the flow field environment of the proximal region of a bypass. A series of different branching models with laminar inflow are considered to systematically investigate the geometrical effect under different flow conditions. Model types (with branch diameter to host diameter ratio $D_2/D_1 < 1$, with or without blend at the junction) include T-junction and host to branch junction with a radius of curvature with and without helical pitch. Some flow conditions included non-Newtonian blood and non-steady flow. Non-blended T-junction is subjected to flow separation at the inner wall of the branch unless the flow rate ratio $(ṁ_2/ṁ_1)$ is high and $D_2$ is small. By employing a blend radius at the T-junction, there is a critical flow rate ratio where separation near the inner wall of the junction can be diminished under steady state flow condition. This parameter is known as $(ṁ_2/ṁ_1)$$_{crit.}$ Given a blended T-junction, there is a common branch radius $r_B$ which corresponds to $(ṁ_2/ṁ_1)$$_{crit,min}$ that gives the minimum separation scale under steady state flow condition or delays the onset of separation under non-steady flow conditions. This parameter was found to be independent of $Re$. A geometric correlation that corresponds to non-separated flow in blended T-junction was developed and can be expressed as $r_B = 0.146 D_2$$^{1.74}$. This correlation is independent to flow rate ratio.","abstract_html":"Aortocoronary bypass (ACB) surgery is a treatment to bypass a blocked artery using a graft. Approximately 500,000 bypass surgeries are performed in the U.S. each year. Of these, about 15% to 20% have an early-phase failure, typically in the proximal region. A natural question which arises is whether fluid dynamic geometry plays a role in the patency. Since only a few studies have considered proximal region geometry, this motivates the present study. Blood flow in a coronary artery bypass often involves very complex fluid dynamic behavior. Numerical simulation is employed to investigate the flow field environment of the proximal region of a bypass. A series of different branching models with laminar inflow are considered to systematically investigate the geometrical effect under different flow conditions. Model types (with branch diameter to host diameter ratio <span class=\"etd-inline-math\">D<sub>2</sub>/D<sub>1</sub> &lt; 1</span>, with or without blend at the junction) include T-junction and host to branch junction with a radius of curvature with and without helical pitch. Some flow conditions included non-Newtonian blood and non-steady flow. Non-blended T-junction is subjected to flow separation at the inner wall of the branch unless the flow rate ratio <span class=\"etd-inline-math\">(ṁ<sub>2</sub>/ṁ<sub>1</sub>)</span> is high and <span class=\"etd-inline-math\">D<sub>2</sub></span> is small. By employing a blend radius at the T-junction, there is a critical flow rate ratio where separation near the inner wall of the junction can be diminished under steady state flow condition. This parameter is known as <span class=\"etd-inline-math\">(ṁ<sub>2</sub>/ṁ<sub>1</sub>)</span><span class=\"etd-inline-math\"><sub>crit.</sub></span> Given a blended T-junction, there is a common branch radius <span class=\"etd-inline-math\">r<sub>B</sub></span> which corresponds to <span class=\"etd-inline-math\">(ṁ<sub>2</sub>/ṁ<sub>1</sub>)</span><span class=\"etd-inline-math\"><sub>crit,min</sub></span> that gives the minimum separation scale under steady state flow condition or delays the onset of separation under non-steady flow conditions. This parameter was found to be independent of $Re$. A geometric correlation that corresponds to non-separated flow in blended T-junction was developed and can be expressed as <span class=\"etd-inline-math\">r<sub>B</sub> = 0.146 D<sub>2</sub></span><span class=\"etd-inline-math\"><sup>1.74</sup></span>. This correlation is independent to flow rate ratio.","abstract_has_math":true,"creators":["Kok, Foo"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-05","date_published":"2015-05","updated_at":"2026-07-24T06:06:34Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["hdl:10057/11599"],"render_values":[{"text":"hdl:10057/11599","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2015-05"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["hdl:10057/11599"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.other","label":"Dc Description Other","values":["Aortocoronary bypass (ACB) surgery is a treatment to bypass a blocked artery using a graft. Approximately 500,000 bypass surgeries are performed in the U.S. each year. Of these, about 15% to 20% have an early-phase failure, typically in the proximal region. A natural question which arises is whether fluid dynamic geometry plays a role in the patency. Since only a few studies have considered proximal region geometry, this motivates the present study. Blood flow in a coronary artery bypass often involves very complex fluid dynamic behavior. Numerical simulation is employed to investigate the flow field environment of the proximal region of a bypass. A series of different branching models with laminar inflow are considered to systematically investigate the geometrical effect under different flow conditions. Model types (with branch diameter to host diameter ratio $D_2/D_1 < 1$, with or without blend at the junction) include T-junction and host to branch junction with a radius of curvature with and without helical pitch. Some flow conditions included non-Newtonian blood and non-steady flow. Non-blended T-junction is subjected to flow separation at the inner wall of the branch unless the flow rate ratio $(ṁ_2/ṁ_1)$ is high and $D_2$ is small. By employing a blend radius at the T-junction, there is a critical flow rate ratio where separation near the inner wall of the junction can be diminished under steady state flow condition. This parameter is known as $(ṁ_2/ṁ_1)$$_{crit.}$ Given a blended T-junction, there is a common branch radius $r_B$ which corresponds to $(ṁ_2/ṁ_1)$$_{crit,min}$ that gives the minimum separation scale under steady state flow condition or delays the onset of separation under non-steady flow conditions. This parameter was found to be independent of $Re$. A geometric correlation that corresponds to non-separated flow in blended T-junction was developed and can be expressed as $r_B = 0.146 D_2$$^{1.74}$. This correlation is independent to flow rate ratio."]},{"key":"dc:title","label":"Title","values":["Numerical analysis of blood flow in an aortocoronary bypass model"]}]}],"canonical_facts":{"dc:date.issued":["2015-05"],"dc:description.other":["Aortocoronary bypass (ACB) surgery is a treatment to bypass a blocked artery using a graft. Approximately 500,000 bypass surgeries are performed in the U.S. each year. Of these, about 15% to 20% have an early-phase failure, typically in the proximal region. A natural question which arises is whether fluid dynamic geometry plays a role in the patency. Since only a few studies have considered proximal region geometry, this motivates the present study. Blood flow in a coronary artery bypass often involves very complex fluid dynamic behavior. Numerical simulation is employed to investigate the flow field environment of the proximal region of a bypass. A series of different branching models with laminar inflow are considered to systematically investigate the geometrical effect under different flow conditions. Model types (with branch diameter to host diameter ratio $D_2/D_1 < 1$, with or without blend at the junction) include T-junction and host to branch junction with a radius of curvature with and without helical pitch. Some flow conditions included non-Newtonian blood and non-steady flow. Non-blended T-junction is subjected to flow separation at the inner wall of the branch unless the flow rate ratio $(ṁ_2/ṁ_1)$ is high and $D_2$ is small. By employing a blend radius at the T-junction, there is a critical flow rate ratio where separation near the inner wall of the junction can be diminished under steady state flow condition. This parameter is known as $(ṁ_2/ṁ_1)$$_{crit.}$ Given a blended T-junction, there is a common branch radius $r_B$ which corresponds to $(ṁ_2/ṁ_1)$$_{crit,min}$ that gives the minimum separation scale under steady state flow condition or delays the onset of separation under non-steady flow conditions. This parameter was found to be independent of $Re$. A geometric correlation that corresponds to non-separated flow in blended T-junction was developed and can be expressed as $r_B = 0.146 D_2$$^{1.74}$. This correlation is independent to flow rate ratio."],"dc:identifier":["hdl:10057/11599"],"dc:title":["Numerical analysis of blood flow in an aortocoronary bypass model"],"dc:type":["Dissertation"]},"updated_at":"2026-07-24T06:06:34Z"}