Analytical Prediction of the Heat Transfer From a Blood Vessel Near the Skin Surface Cooled by a Symmetrical Strip

1975 ◽  
Vol 97 (1) ◽  
pp. 61-65 ◽  
Author(s):  
J. C. Chato ◽  
A. Shitzer
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Steady State ◽  
Carotid Artery ◽  
Blood Vessel ◽  
Analytical Method ◽  
Skin Surface ◽  
Analytical Prediction ◽  
Flow Through ◽  
Optimum Width

A steady-state analytical method has been developed to estimate the amount of heat extracted from a blood vessel running close to the skin surface which is cooled in a symmetrical fashion by a cooling strip. The results indicate that the optimum width of a cooling strip is approximately three times the depth to the centerline of the blood vessel. The heat extracted from a blood vessel similar to the carotid artery by such a strip is about 0.9 w/m-deg C, which is too small to affect significantly the temperature of the blood flow through a main blood vessel, such as the carotid artery.

Modeling Transient Heat Transfer Through the Skin and Superficial Tissues—1: Surface Insulation

1986 ◽  
Vol 108 (2) ◽  
pp. 183-188 ◽  
Author(s):  
D. A. Hodson ◽  
G. Eason ◽  
J. C. Barbenel
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Analytical Solutions ◽  
Numerical Solutions ◽  
Transient Heat Transfer ◽  
Transient Problem ◽  
Finite Slab ◽  
Infinite Slab ◽  
Flow Through ◽  
Superficial Tissues

Two models of transient heat transfer through the skin and superficial tissues are presented. One model comprises a finite slab and semi-infinite slab, representing the epidermis and subdermal tissues, respectively, and a heat-generating interface representing the thermal effect of blood flow through the dermis. A model is also considered where the three tissue regions are represented more conventionally by three finite slabs. A transient problem arising from surface insulation is examined and analytical solutions derived from the first model are compared with numerical solutions derived from the second.

Performance Indicators for Steady-State Heat Transfer Through Fin Assemblies

1996 ◽  
Vol 118 (2) ◽  
pp. 310-316 ◽  
Author(s):  
A. S. Wood ◽  
G. E. Tupholme ◽  
M. I. H. Bhatti ◽  
P. J. Heggs
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Heat Flow ◽  
Performance Indicators ◽  
Physical Parameters ◽  
State Heat ◽  
Extended Surface ◽  
Flow Through ◽  
Steady State Heat ◽  
Steady State Heat Transfer

A comparative study is presented of several models describing steady-state heat flow through an assembly consisting of a primary surface (wall) and attached extended surface (fin). Attention is focused on the validity of four performance indicators. The work shows that the augmentation factor is the only indicator capable of correctly predicting the behavioral trends of the rate of heat flow through the assembly as the influencing physical parameters are varied.

Comparison of Effects of Vitamin E and Wen-jing-tang (Unkei-to), An Herbal Medicine, on Peripheral Blood Flow in Post-menopausal Women with Chilly Sensation in the Lower Extremities: A Randomized Prospective Study

2006 ◽  
Vol 34 (06) ◽  
pp. 969-979 ◽  
Author(s):  
Takahisa Ushiroyama ◽  
Kou Sakuma ◽  
Sakura Nosaka
Keyword(s):  
Blood Flow ◽  
Vitamin E ◽  
Herbal Medicine ◽  
Peripheral Blood ◽  
Lower Extremities ◽  
Skin Surface ◽  
Laser Doppler ◽  
Peripheral Blood Flow ◽  
Perimenopausal Women ◽  
Flow Through

We examined the association between blood flow and chilly sensation in the lower extremities, comparing the changes in blood flow induced by the vitamin E and herbal therapy (Wen-jing-tang) in perimenopausal women with chilly sensation. One hundred sixty-one perimenopausal women aged 42–61 years (mean: 50.4 ± 3.8 years) with chilly sensation in the lower extremities participated in the study. The participants were randomized for treatment with Wen-jing-tang or a vitamin E preparation containing 600 mg tocopherol nictinate per day for 8 weeks. Blood flow measurement was performed by laser Doppler fluxmetry to determine tissue under the jaw, in the middle finger, and in the third toe. Wen-jing-tang significantly increased the peripheral blood flow in the skin surface in the tiptoe (12.8 ± 8.8, p = 0.0068) from basal levels (6.0 ± 5.1), although no significant change was observed in the blood flow in fingertip or under the jaw during treatment. The rate of increase of blood flow in the skin surface of in the lower extremities was significantly higher in the Wen-jing-tang treating group (116.4 ± 46.5%) than in the vitamin E group (39.8 ± 21.3%)( p < 0.0001). When the effects of herbal treatment and vitamin E treatment were compared in the subjects with baseline upper extremity blood flow above the mean + 1.5 SD, mean blood flow through the upper extremities was found to have been significantly decreased after Wen-jing-tang treatment (from 57.7 ± 4.8 to 43.1 ± 4.2, p = 0.0277), whereas it remained unchanged after treatment with vitamin E. Classical monographs described Wen-jing-tang as being particularly useful in curing chilly sensation in lower extremities. The present study using a laser Doppler fluxmeter demonstrated that treatment with this herbal medicine significantly increased blood flow through the periphery of lower extremities in patients with chilly sensation. It also showed that this herbal medicine suppresses excessive blood flow through the upper half of the body and thus stimulates restoration of physiological distribution of blood flow throughout the entire body.

Analysis of the Weinbaum-Jiji Model of Blood Flow in the Canine Kidney Cortex for Self-Heated Thermistors

1994 ◽  
Vol 116 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Jonathan W. Valvano ◽  
Sungwoo Nho ◽  
Gary T. Anderson
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Steady State ◽  
Dominant Role ◽  
Kidney Cortex ◽  
Transfer Model ◽  
Actual Length ◽  
Physical Measurements ◽  
Continuous Power ◽  
Canine Kidney

The Weinbaum-Jiji equation can be applied to situations where: 1) the vascular anatomy is known; 2) the blood velocities are known; 3) the effective modeling volume includes many vessels; and 4) the vessel equilibration length is small compared to the actual length of the vessel. These criteria are satisfied in the situation where steady-state heated thermistors are placed in the kidney cortex. In this paper, the Weinbaum-Jiji bioheat equation is used to analyze the steady state response of four different sized self-heated thermistors in the canine kidney. This heat transfer model is developed based on actual physical measurements of the vasculature of the canine kidney cortex. In this model, parallel-structured interlobular arterioles and venules with a 60 μm diameter play the dominant role in the heat transfer due to blood flow. Continuous power is applied to the thermistor, and the instrument measures the resulting steady state temperature rise. If an accurate thermal model is available, perfusion can be calculated from these steady-state measurements. The finite element simulations correlate well in shape and amplitude with experimental results in the canine kidney. In addition, this paper shows that the Weinbaum-Jiji equation can not be used to model the transient response of the thermistor because the modeling volume does not include enough vessels and the vessel equilibration length is not small compared to the actual length of the vessel.

Smooth Mesh Generation for Numerical Analysis of Blood Vessel Fluid Flow

2011 ◽  
Author(s):  
Juraj Culak ◽  
Yulia V. Peet ◽  
David L. Chopp
Keyword(s):  
Blood Flow ◽  
Image Segmentation ◽  
Fluid Flow ◽  
Numerical Analysis ◽  
Carotid Artery ◽  
Blood Vessel ◽  
Mesh Generation ◽  
Patient Specific ◽  
High Quality

A Matlab-based approach to image segmentation and mesh generation for creating high-quality hexagonal meshes is developed. The successful use of the procedure in patient-specific simulations of blood flow in a carotid artery is demonstrated.

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