Welcome to this special edition of the SoftInWay blog! While we at SoftInWay are known for helpful articles about designing various machines, retrofitting, and rotordynamics, we believe it is also important to examine the lives of some of the men and women behind these great machines.
The compound steam turbine is one of the greatest inventions, not just in turbomachinery but around the world. Once it was introduced to the marine industry, the steam turbine exploded in popularity as a means of allowing ships to travel faster and farther than ever before. It would go on to become a critical part in the naval arms race that preceded the First World War. The steam turbine not only revolutionized marine and naval propulsion, it became one of the best ways to generate electricity. After its inception, the steam turbine became one of the best ways to reliably generate power on a large scale, and make electricity the regular utility that it is today. But who invented the modern steam turbine?
Sir Charles Algernon Parsons, (1854 – 1931), is the inventor of the modern steam turbine. The work he undertook in his life had a massive impact on the world, continuing the legacy of James Watt by bringing steam technology into the modern era. Born on June 13th 1854 into an Anglo-Irish family, Sir Charles Parsons was born into a well-respected family with roots in County Offaly, Ireland. In fact the town now known as Birr was then known as Parsonstown, from the early 1600’s through to 1899. Parsons was the sixth son of the 3rd Earl of Rosse, and had a family lineage that had made great strides in the areas of military, political, and physical science. The family’s castle in Birr, which is still owned by the Parsons family and is the permanent residence of the 7th Earl of Rosse, was a rendezvous for men of science during the childhood of Sir Charles. Suffice it to say, there was no better place for a future-engineer to grow up. He alongside his brothers would receive private tutorship from Sir Robert Ball and Dr Johnstone Stoney, famous Irish astronomer and physicist, respectively.
After receiving private tutoring, Sir Charles went onto university at the age of 17. He attended Trinity College, Dublin, studying mathematics before going to Saint John’s College Cambridge, where he graduated with first honors. It should be noted that at the time there was not an engineering school at Cambridge, however Parsons did attend engineering lectures that covered applied mechanics; his studies were so successful that he graduated as Eleventh Wrangler in his class in 1877. Armed with the knowledge of mathematics and mechanical engineering, Sir Charles set out into the professional world, starting with an apprenticeship (a notably lowly position for someone of his heritage and stature) in the Elswick works of Sir William Armstrong and Co. After that he moved on to Kiston and Co. based out of Yorkshire, where his work included developing a high speed four-cylinder steam engine as well as work on rocket-powered torpedoes.
It was in 1884 that Sir Charles Parsons would begin his legacy of massive impacts on mechanical and electrical engineering, when he got a position as the director of electrical equipment department at Clarke, Chapman and Company. He began work on a steam turbine, which would utilize the velocity of steam to spin a machine on its axis, rather than utilize the pressure of the steam to force a piston to reciprocate back and forth. The challenge with designing such a machine, is the need for a relatively high velocity rotor with blades on its circumference to make efficient use of the steam’s high velocity. In short, no machine could be designed to absorb the energy of steam’s velocity effectively. Lower pressure steam can travel at 2500 feet per second, which translates into more than 1700 miles per hour. In order to make efficient use of the steam, the turbine would have to travel at half the speed of the steam; this was not possible without serious workarounds. The centrifugal force of such a high rotation, and other rotor dynamic behavior, would jeopardize the machine’s integrity, and could lead to serious damage or destruction. James Watt, famous for his invention of the steam engine, had recognized this when he was in business, and more or less dismissing steam turbines as unfeasible without the action of divine Providence. Sir Charles, however, had that workaround.
He got to work on designing a rotor enclosed in a casing, where the escaping steam’s velocity could be better controlled by allowing the steam to expand in steps or stages. RH Parsons does quite a good job of explaining the concept of Parson’s turbine in this online copy of The Steam Turbine and other Inventions of Sir Charles Parsons, writing:
To put this idea into effect he constructed a turbine consisting of a cylindrical rotor enclosed in a casing. The steam flowed along the annulus between the two, parallel to the axis of the machine, and in so doing it had to pass through rings of blades fixed alternately in the casing and rotor. The passages between the blades of each ring formed virtually a set of nozzles in which a partial expansion of the steam could take place. In passing through each ring of fixed blades the steam acquired a certain velocity due to this expansion, and the jets so formed gave up their energy in driving the succeeding row of moving blades. The passages between the latter blades also acted as nozzles, permitting a further partial expansion, so that the moving blades were impelled partly by the ‘action’ of the steam entering them and partly by the ‘reaction’ of the steam leaving them.
In short, Sir Charles created the multi-stage reaction steam turbine. Efficient steam expansion was not his only problem though, he had to consider other important factors like creating a new bearing that could “bear” the load of a rotor that moved at 50 times the speed of the fastest reciprocating steam engine of the day. He also understood that this bearing would need to be lubricated, and that the axial force of the steam’s expansion on the rotor, would be better controlled by having the steam enter the flowpath at the rotor’s middle point, and then expand outwards, instead of following one linear path.
The flowpath of the turbine, would look like what’s seen in the above picture, where the stages are symmetrically split on the rotor, and allow for the steam to flow along the axis of the turbine equally in both directions minimizing the axial thrust being exerted on the machine. He would also invent a kind of “dummy piston” so that smaller machines could be designed by not utilizing the method above, and instead have one singular flowpath like what is seen in the picture below.
By ensuring the machine’s rotor dynamics were accounted for, the steam turbine could operate safely using its new kind of bearings.
Alongside the invention of this steam turbine, Sir Charles also invented a dynamo that could be directly linked to his turbine and be able to rotate at an astonishing 18,000 revolutions per minute. By doing so, the steam turbine could generate electricity more efficiently than any previous steam engine. It wasn’t long before the virtues of the steam turbine and its specially made dynamo would become popular. By 1888, more than 200 of these turbomachines were in use. These turbo-generators would first find popularity at sea, as ship-board electricity generation, before exploding in popularity on land as easily scalable and suitable replacements for larger, less efficient reciprocating steam engines.
Sir Charles’s creation would soon revolutionize power generation. After a difficult first few years where the turbine was unable to turn heads, it soon came into its own. In 1894 the steam turbine-powered generators would end up saving the main station of the Metropolitan Electric Supply co. from closing down in London due to the excess noise created by the reciprocating power generators.As more of these machines that were grander in scale were called for, Parsons created Messrs C. A. Parsons and Co., Ltd. By the turn of the century, Sir Charles’s company was creating generating sets with an output of 1,000 kilowatts. In 1912, he and his company created a 25,000kW turbo-generator, which was “by far the largest and most efficient generating unit in the world at the time.”. By 1923, a single turbo-generator from his company was able to generate 200,000kW, and had rendered the reciprocating steam engine obsolete. The steam turbine was the ultimate power generator, and made electricity the common utility that it is today.
The steam turbine’s popularity at sea would become more prevalent through the turn of the century, and not just as a means of generating electricity. After forming his own company, called The Parsons Marine Steam Turbine Co., Ltd., he began work on a now-famous small ship called The Turbinia.
At 100 feet long and 44 tons, Turbinia was not the largest ship afloat. She would, however, become one of the fastest. Thanks to her special steam turbine propulsion system, she would be one of the fastest vessels afloat. At a special celebration of Queen Victoria’s diamond jubilee in 1897, Turbinia raced past the much slower line of Royal Navy ships at 34 knots ( nearly 40 miles per hour!). The Royal Navy’s destroyers of the time were only capable of barely reaching 27 knots with their outdated reciprocating engines. Parson’s steam turbine could not be ignored.
After making a splash at the Jubilee, Sir Charles’s steam turbines were in high demand. His company was subsequently contracted to create the propulsion systems for the Royal Navy destroyers H.M.S. Viper and H.M.S. Cobra. H.M.S Viper’s steam turbines would put out a whopping 12,000 horsepower, and could propel Viper up to a blistering 37 knots. Although the Viper and Cobra were not in existence for long, they alongside Turbinia paved the way for the steam turbine’s popularity as the primary mover for oceangoing vessels.
Some of the most famous ships to sail the seas would use Parson steam turbines, including the R.M.S. Mauretania and Lusitania, the H.M.S. Dreadnought, and even the R.M.S Titanic had a steam turbine built by Sir Charles’s company.
Although not nearly as common as they were decades ago, ships are still propelled by steam turbines today. Whether they use fuel oil or nuclear heat to generate steam, Sir Charles Parsons’s inventions revolutionized marine transportation in unimaginable ways.
Sir Charles Parsons would invent other machinery not covered in this blog throughout his life, including different screw propellers that can be seen on the Turbinia as well as mechanical gearboxes to maximize the efficiencies of his steam turbines both on land and at sea. According to Mark Crawford on the ASME website, “Parsons spent much of his free time working on new ideas and inventions. He experimented with gearing, telescopes, and even dabbled in chemistry with attempts to crystallize carbon. Among his other inventions is the auxetophone, a device that amplified stringed musical instruments.” Sir Charles Algernon Parsons would pass away in 1931 from neuritis while on vacation at sea.
Although steam turbines are not as common as they once were, they won’t be going anywhere anytime soon. Moreover, the principles that Sir Charles utilized to create his steam turbine are the foundation of good turbomachinery design today; and any engineer working with turbines should be familiar with him and his legacy.