Henry Herbert Rachford Jr.

14 June, 192531 October, 2022
Obituary of Henry Herbert Rachford Jr.
Henry H. Rachford, Jr. passed away in Houston on Monday, the 31st of October 2022. He was 97 years of age. Henry was born on the 14th of June 1925, in El Dorado, Arkansas to Henry H. Rachford, Sr. and Helene Akin Rachford. The family moved to Houston when Henry was a young boy. He graduated from Lamar High School in 1942. He earned his B.S. Chemical Engineering (1945) and M.A. Chemistry (1947) from Rice University. He earned his Sc.D. Chemical Engineering (1950) from Massachusetts Institute of Technology (MIT). Henry was both a visionary and a problem solver. After MIT, he started his career at Humble Oil and Refining Company (now ExxonMobil). Henry saw that the primitive computing machines of the early 1950s would develop into important tools for science and engineering. Problems that could not be solved by analytic methods could be approximately solved by numerical computation. The methods that were available were also primitive, being either very slow or requiring unrealistically large amounts of memory. Henry led a group at Humble investigating the uses of digital computing machines. One of his early contributions was a method of computing vapor/liquid equilibria for hydrocarbons. Published in 1952, this technique is still widely used today: the Rachford (John) Rice method. In late 1953, Henry and his Humble colleagues made the high-profile invention of Alternating Direction Implicit (ADI). With the invention of ADI methods, they produced one of the first, possibly the first, computational method that demonstrated that solving several simpler problems could be used to solve much more complicated physical problems. Their target was to be able to simulate the behavior of oil reservoirs over decades, but it was clear to groups around the world that the methods Henry and crew had produced could be generalized to simulate a very wide range of physical phenomena. When these discoveries became public in 1955, Henry and two of his close colleagues became scientific celebrities on a world scale. The three seminal papers from that period still receive hundreds of citations every year. The operator splitting techniques that are the generalizations of ADI are used in simulating oil reservoirs, many industrial processes, weather, climate, exploding stars (super nova), and more. Of course, Henry did not stop doing science and engineering after this major advance. He had an 18-year career as a professor of Mathematics and Mathematical Sciences at Rice University, where he mentored nine PhD students, and has at least 163 mathematical descendants. He made major contributions to the understanding of finite element methods for approximating solutions of partial differential equations. Henry co-founded a company that devised new techniques for simulation of commercial pipeline networks. The company still exists as a part of DNV GL, for which Henry continued to work until he was 92 years old. The tools produced by this company are used for design of pipelines, leak detection, training pipeline operators, among others. Henry received many honors for his scientific and engineering work. Two notable ones are: Society of Industrial and Applied Mathematics (SIAM) Fellow (2009) (for contributions to the numerical solution of partial differential equations and applications) and National Academy of Engineering (2000) (for contributions in the numerical solution of partial differential equations to solve petroleum reservoir and pipeline hydraulics problems). Henry met his future wife, Josephine “Jo” Hiett, while they were both working at Humble. Amazingly, Jo got him away from work and to the altar for their wedding in 1957. They had two daughters, Susan and Laurie, neither of whom were Henry’s mathematical descendants. Henry and Jo loved to travel, particularly in Europe. Henry (the photographer) and Jo (the walking travel book) did not miss seeing any cathedral, museum, castle, or other historic site, and gave their girls many memorable experiences they appreciate to this day. Henry developed a love of fine wine and a refined palate during many trips to Burgundy and Bordeaux, and acquired an impressive wine collection. Henry was a gifted pianist from an early age and especially loved playing the works of Chopin on a baby grand that his parents had given to their child prodigy. As his work demonstrates, Henry was always a man before his time. This includes life on the home front. In the early 1970s, he brought home a precursor to a PC, which was a mega computer (the size of a console TV) to do his work, but made the mistake of teaching his daughter how to kill Klingons and Romulans on a very slow dial up version of a Star Trek game. As a precursor to the Walkman (not to mention the iPhone), Henry jogged the neighborhood carrying a reel-to-reel tape player so he could learn languages for his math lectures in German (Munich), French (Paris), and Czech (Prague). After Jo passed away in 1981, Henry found love again and married Sylvia Ann Brown in 1983. They met in the chancel choir at St. Luke’s United Methodist Church and they later joined St. Paul’s United Methodist Church and its chancel choir. They shared a love of music and performing in chancel choirs, the Chamber Choir (including performances in Ely Cathedral, in Ely, Cambridgeshire, England), and with the Houston Masterworks Chorus. Henry and Sylvia loved to travel. They also enjoyed hosting pool parties for family and friends, and sharing Henry’s famous smoked chicken and Cuba Libres. Henry is predeceased by his parents; his first wife Jo; and his second wife Sylvia. He is survived by his daughters, Susan Rachford Imre (husband Tom) and Laurie Rachford; his three grandchildren, Stephanie Fallon (husband Aaron), Chris Lohmann (wife Amy), and Alex Imre; and his great-granddaughter, Poesy Fallon. The family would like to thank the staff at Belmont Village Hunter’s Creek, who cared for Henry over the last three years, Sharona Jacobs with the Elder Advisory Group, and for the wonderful care providers from the Allied Health Team (especially Todd Lampkin and Nakii Barnes) for their kindness, care, thoughtfulness and compassion. The memorial service is to be conducted at two o’clock in the afternoon on Saturday, the 12th of November, in the Jasek Chapel of Geo. H. Lewis & Sons, 1010 Bering Drive in Houston, where Rev. Andrew Wolfe, Associate Pastor of Congregational Care for St. Paul’s United Methodist Church, is to officiate. Immediately following, all are invited to greet the family and share remembrances during a reception to be held in the adjacent grand foyer. In lieu of customary remembrances, the family requests with gratitude that memorial contributions in Henry’s memory be directed to the Rice Annual Fund at Rice University MS-81, PO Box 1892, Houston, TX 77251 (, the Houston Symphony Society, 615 Louisiana St, Houston, TX 77002 (, or the charity of your choice.

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Saturday, 12 November, 2022

Memorial Service