# Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems

## Abstract

We present a moment-based acceleration algorithm applied to Monte Carlo simulation of thermal radiative-transfer problems. Our acceleration algorithm employs a continuum system of moments to accelerate convergence of stiff absorption–emission physics. The combination of energy-conserving tallies and the use of an asymptotic approximation in optically thick regions remedy the difficulties of local energy conservation and mitigation of statistical noise in such regions. We demonstrate the efficiency and accuracy of the developed method. We also compare directly to the standard linearization-based method of Fleck and Cummings [1]. A factor of 40 reduction in total computational time is achieved with the new algorithm for an equivalent (or more accurate) solution as compared with the Fleck–Cummings algorithm.

- Authors:

- Bettis Atomic Power Laboratory, P.O. Box 79, West Mifflin, PA 15122 (United States)
- Fluid Dynamics and Solid Mechanics Group, Los Alamos National Laboratory, P.O. Box 1663, MS B216, Los Alamos, NM 87545 (United States)
- Computational Physics and Methods Group, Los Alamos National Laboratory, P.O. Box 1663, MS D409, Los Alamos, NM 87545 (United States)

- Publication Date:

- OSTI Identifier:
- 22465600

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Journal of Computational Physics; Journal Volume: 284; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 97 MATHEMATICAL METHODS AND COMPUTING; ABSORPTION; ACCURACY; ALGORITHMS; ASYMPTOTIC SOLUTIONS; COMPUTERIZED SIMULATION; CONVERGENCE; EFFICIENCY; EMISSION; ENERGY CONSERVATION; MONTE CARLO METHOD; RADIANT HEAT TRANSFER; STATISTICS

### Citation Formats

```
Densmore, J.D., E-mail: jeffery.densmore@unnpp.gov, Park, H., E-mail: hkpark@lanl.gov, Wollaber, A.B., E-mail: wollaber@lanl.gov, Rauenzahn, R.M., E-mail: rick@lanl.gov, and Knoll, D.A., E-mail: nol@lanl.gov.
```*Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems*. United States: N. p., 2015.
Web. doi:10.1016/J.JCP.2014.12.020.

```
Densmore, J.D., E-mail: jeffery.densmore@unnpp.gov, Park, H., E-mail: hkpark@lanl.gov, Wollaber, A.B., E-mail: wollaber@lanl.gov, Rauenzahn, R.M., E-mail: rick@lanl.gov, & Knoll, D.A., E-mail: nol@lanl.gov.
```*Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems*. United States. doi:10.1016/J.JCP.2014.12.020.

```
Densmore, J.D., E-mail: jeffery.densmore@unnpp.gov, Park, H., E-mail: hkpark@lanl.gov, Wollaber, A.B., E-mail: wollaber@lanl.gov, Rauenzahn, R.M., E-mail: rick@lanl.gov, and Knoll, D.A., E-mail: nol@lanl.gov. Sun .
"Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems". United States.
doi:10.1016/J.JCP.2014.12.020.
```

```
@article{osti_22465600,
```

title = {Monte Carlo simulation methods in moment-based scale-bridging algorithms for thermal radiative-transfer problems},

author = {Densmore, J.D., E-mail: jeffery.densmore@unnpp.gov and Park, H., E-mail: hkpark@lanl.gov and Wollaber, A.B., E-mail: wollaber@lanl.gov and Rauenzahn, R.M., E-mail: rick@lanl.gov and Knoll, D.A., E-mail: nol@lanl.gov},

abstractNote = {We present a moment-based acceleration algorithm applied to Monte Carlo simulation of thermal radiative-transfer problems. Our acceleration algorithm employs a continuum system of moments to accelerate convergence of stiff absorption–emission physics. The combination of energy-conserving tallies and the use of an asymptotic approximation in optically thick regions remedy the difficulties of local energy conservation and mitigation of statistical noise in such regions. We demonstrate the efficiency and accuracy of the developed method. We also compare directly to the standard linearization-based method of Fleck and Cummings [1]. A factor of 40 reduction in total computational time is achieved with the new algorithm for an equivalent (or more accurate) solution as compared with the Fleck–Cummings algorithm.},

doi = {10.1016/J.JCP.2014.12.020},

journal = {Journal of Computational Physics},

number = ,

volume = 284,

place = {United States},

year = {Sun Mar 01 00:00:00 EST 2015},

month = {Sun Mar 01 00:00:00 EST 2015}

}