Misplaced Pages

#836163

74-665: SS Khedive Ismail , formerly SS Aconcagua , was a turbine steamship that was built in 1922 as an ocean liner , converted into a troop ship in 1940 and sunk by a Japanese submarine in 1944 with great loss of life. She was owned by the Chilean company CSAV 1922–1932, the Scottish William Hamilton & Co (1932–35), the Egyptian company KML 1935–1940 and the British Ministry of War Transport 1940–1944. In April 1920

148-536: A d e E n e r g y   s u p p l i e d   p e r   s t a g e = U Δ V w Δ h {\displaystyle {\eta _{\mathrm {stage} }}={\frac {\mathrm {Work~done~on~blade} }{\mathrm {Energy~supplied~per~stage} }}={\frac {U\Delta V_{w}}{\Delta h}}} Where Δ h = h 2 − h 1 {\displaystyle \Delta h=h_{2}-h_{1}}

222-563: A quality near 90%. Non-condensing turbines are most widely used for process steam applications, in which the steam will be used for additional purposes after being exhausted from the turbine. The exhaust pressure is controlled by a regulating valve to suit the needs of the process steam pressure. These are commonly found at refineries, district heating units, pulp and paper plants, and desalination facilities where large amounts of low pressure process steam are needed. Reheat turbines are also used almost exclusively in electrical power plants. In

296-671: A Heat Engine) was published in Berlin in 1903. A further book Dampf und Gas-Turbinen (English: Steam and Gas Turbines) was published in 1922. The Brown-Curtis turbine , an impulse type, which had been originally developed and patented by the U.S. company International Curtis Marine Turbine Company, was developed in the 1900s in conjunction with John Brown & Company . It was used in John Brown-engined merchant ships and warships, including liners and Royal Navy warships. The present day manufacturing industry for steam turbines consists of

370-457: A combined heating surface of 17,832 square feet (1,657 m). These fed steam at 215 lb f /in to four steam turbines that drove twin propeller shafts by single-reduction gearing. The turbines had a combined rating of 1,469 NHP and gave the ship a speed of 17 knots (31 km/h). By the time Aconcagua and Teno entered service they faced strong competition from Grace Line , and CSAV reported losses in 1922 and 1923. However, from 1922

444-444: A common reduction gear, with a geared cruising turbine on one high-pressure turbine. The moving steam imparts both a tangential and axial thrust on the turbine shaft, but the axial thrust in a simple turbine is unopposed. To maintain the correct rotor position and balancing, this force must be counteracted by an opposing force. Thrust bearings can be used for the shaft bearings, the rotor can use dummy pistons, it can be double flow -

518-456: A generator. Tandem compound are used where two or more casings are directly coupled together to drive a single generator. A cross compound turbine arrangement features two or more shafts not in line driving two or more generators that often operate at different speeds. A cross compound turbine is typically used for many large applications. A typical 1930s-1960s naval installation is illustrated below; this shows high- and low-pressure turbines driving

592-644: A reaction turbine that was put to work there. In 1807, Polikarp Zalesov designed and constructed an impulse turbine, using it for the fire pump operation. In 1827 the Frenchmen Real and Pichon patented and constructed a compound impulse turbine. The modern steam turbine was invented in 1884 by Charles Parsons , whose first model was connected to a dynamo that generated 7.5 kilowatts (10.1 hp) of electricity. The invention of Parsons' steam turbine made cheap and plentiful electricity possible and revolutionized marine transport and naval warfare. Parsons' design

666-408: A reheat turbine, steam flow exits from a high-pressure section of the turbine and is returned to the boiler where additional superheat is added. The steam then goes back into an intermediate pressure section of the turbine and continues its expansion. Using reheat in a cycle increases the work output from the turbine and also the expansion reaches conclusion before the steam condenses, thereby minimizing

740-448: A row of moving blades, with multiple stages for compounding. This is also known as a Rateau turbine, after its inventor. A velocity-compounded impulse stage (invented by Curtis and also called a "Curtis wheel") is a row of fixed nozzles followed by two or more rows of moving blades alternating with rows of fixed blades. This divides the velocity drop across the stage into several smaller drops. A series of velocity-compounded impulse stages

814-1371: A single stage impulse turbine). Therefore, the maximum value of stage efficiency is obtained by putting the value of U V 1 = 1 2 cos ⁡ α 1 {\displaystyle {\frac {U}{V_{1}}}={\frac {1}{2}}\cos \alpha _{1}} in the expression of η b {\displaystyle \eta _{b}} . We get: η b max = 2 ( ρ cos ⁡ α 1 − ρ 2 ) ( 1 + k c ) = 1 2 cos 2 ⁡ α 1 ( 1 + k c ) {\displaystyle {\eta _{b}}_{\text{max}}=2\left(\rho \cos \alpha _{1}-\rho ^{2}\right)(1+kc)={\frac {1}{2}}\cos ^{2}\alpha _{1}(1+kc)} . For equiangular blades, β 1 = β 2 {\displaystyle \beta _{1}=\beta _{2}} , therefore c = 1 {\displaystyle c=1} , and we get η b max = 1 2 cos 2 ⁡ α 1 ( 1 + k ) {\displaystyle {\eta _{b}}_{\text{max}}={\frac {1}{2}}\cos ^{2}\alpha _{1}(1+k)} . If

SECTION 10

#1732858616837

888-469: A spread of four torpedoes, two of which hit Khedive Ismail . The troop ship's stern was engulfed in flame and smoke and she sank in three minutes. As the convoy's merchant ships scattered for safety, Paladin lowered boats to rescue survivors and Petard released depth charges . The troop ship had sunk too quickly to launch any lifeboats, but her Carley floats floated free and some survivors were able to board them. After three patterned releases I-27

962-500: A steam pressure drop and velocity increase as steam moves through the nozzles. Nozzles move due to both the impact of steam on them and the reaction due to the high-velocity steam at the exit. A turbine composed of moving nozzles alternating with fixed nozzles is called a reaction turbine or Parsons turbine . Except for low-power applications, turbine blades are arranged in multiple stages in series, called compounding , which greatly improves efficiency at low speeds. A reaction stage

1036-401: A valve, or left uncontrolled. Extracted steam results in a loss of power in the downstream stages of the turbine. Induction turbines introduce low pressure steam at an intermediate stage to produce additional power. These arrangements include single casing, tandem compound and cross compound turbines. Single casing units are the most basic style where a single casing and shaft are coupled to

1110-399: Is a row of fixed nozzles followed by a row of moving nozzles. Multiple reaction stages divide the pressure drop between the steam inlet and exhaust into numerous small drops, resulting in a pressure-compounded turbine. Impulse stages may be either pressure-compounded, velocity-compounded, or pressure-velocity compounded. A pressure-compounded impulse stage is a row of fixed nozzles followed by

1184-547: Is appreciably less than V 2 {\displaystyle V_{2}} , we get Δ h ≈ 1 2 V 2 2 {\displaystyle {\Delta h}\approx {\frac {1}{2}}{V_{2}}^{2}} . Furthermore, stage efficiency is the product of blade efficiency and nozzle efficiency, or η stage = η b η N {\displaystyle \eta _{\text{stage}}=\eta _{b}\eta _{N}} . Nozzle efficiency

1258-458: Is called a pressure-velocity compounded turbine. By 1905, when steam turbines were coming into use on fast ships (such as HMS  Dreadnought ) and in land-based power applications, it had been determined that it was desirable to use one or more Curtis wheels at the beginning of a multi-stage turbine (where the steam pressure is highest), followed by reaction stages. This was more efficient with high-pressure steam due to reduced leakage between

1332-436: Is composed of different regions of composition. A uniform dispersion of the gamma-prime phase – a combination of nickel, aluminum, and titanium – promotes the strength and creep resistance of the blade due to the microstructure. Refractory elements such as rhenium and ruthenium can be added to the alloy to improve creep strength. The addition of these elements reduces the diffusion of the gamma prime phase, thus preserving

1406-422: Is connected to the casing and one set of rotating blades is connected to the shaft. The sets intermesh with certain minimum clearances, with the size and configuration of sets varying to efficiently exploit the expansion of steam at each stage. An impulse turbine has fixed nozzles that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which is converted into shaft rotation by

1480-436: Is considered to be an isentropic process , or constant entropy process, in which the entropy of the steam entering the turbine is equal to the entropy of the steam leaving the turbine. No steam turbine is truly isentropic, however, with typical isentropic efficiencies ranging from 20 to 90% based on the application of the turbine. The interior of a turbine comprises several sets of blades or buckets . One set of stationary blades

1554-470: Is given by η N = V 2 2 2 ( h 1 − h 2 ) {\displaystyle \eta _{N}={\frac {{V_{2}}^{2}}{2\left(h_{1}-h_{2}\right)}}} , where the enthalpy (in J/Kg) of steam at the entrance of the nozzle is h 1 {\displaystyle h_{1}} and the enthalpy of steam at

SECTION 20

#1732858616837

1628-594: Is not a priority in astern turbines, so only a few stages are used to save cost. A major challenge facing turbine design was reducing the creep experienced by the blades. Because of the high temperatures and high stresses of operation, steam turbine materials become damaged through these mechanisms. As temperatures are increased in an effort to improve turbine efficiency, creep becomes significant. To limit creep, thermal coatings and superalloys with solid-solution strengthening and grain boundary strengthening are used in blade designs. Protective coatings are used to reduce

1702-444: Is the angular velocity of the turbine, then the blade speed is U = ω r {\displaystyle U=\omega r} . The power developed is then W = m ˙ U ( Δ V w ) {\displaystyle W={\dot {m}}U(\Delta V_{w})} . Blade efficiency ( η b {\displaystyle {\eta _{b}}} ) can be defined as

1776-421: Is the specific enthalpy drop of steam in the nozzle. By the first law of thermodynamics : h 1 + 1 2 V 1 2 = h 2 + 1 2 V 2 2 {\displaystyle h_{1}+{\frac {1}{2}}{V_{1}}^{2}=h_{2}+{\frac {1}{2}}{V_{2}}^{2}} Assuming that V 1 {\displaystyle V_{1}}

1850-499: Is to increase the relative velocity at the exit. Therefore, the relative velocity at the exit V r 2 {\displaystyle V_{r2}} is always greater than the relative velocity at the inlet V r 1 {\displaystyle V_{r1}} . SS Mohamed Ali El-Kebir Too Many Requests If you report this error to the Wikimedia System Administrators, please include

1924-499: The Argolic Gulf in the eastern Peloponnese . Luftwaffe aircraft attacked the convoy en route to Nauplia, damaging Slamat and wounding several people aboard Khedive Ismail . Two days before they arrived, the troop ship Ulster Prince had run aground blocking access to Nauplia Port, and on 25 April an air raid had turned her into a total loss. Khedive Ismail , Slamat and their Royal Navy escorts would now have to anchor in

1998-576: The Chilean Compañía Sud Americana de Vapores (CSAV) ordered a pair of passenger and cargo liners for service between Valparaíso and New York via the Panama Canal . Construction was delayed, the ships were not completed until the latter part of 1922, and CSAV lost money as a result. The first ship was launched on 11 February 1922 and completed in August. She was named Aconcagua after

2072-528: The control volume is equal to the net time change of angular momentum flux through the control volume. The swirling fluid enters the control volume at radius r 1 {\displaystyle r_{1}} with tangential velocity V w 1 {\displaystyle V_{w1}} and leaves at radius r 2 {\displaystyle r_{2}} with tangential velocity V w 2 {\displaystyle V_{w2}} . A velocity triangle paves

2146-409: The fatigue resistance, strength, and creep resistance. Turbine types include condensing, non-condensing, reheat, extracting and induction. Condensing turbines are most commonly found in electrical power plants. These turbines receive steam from a boiler and exhaust it to a condenser . The exhausted steam is at a pressure well below atmospheric, and is in a partially condensed state, typically of

2220-652: The 22,837 feet (6,961 m) Aconcagua mountain, the highest in the Andes . Her sister ship , Teno , was launched on 5 September 1922, completed in December and reached Chile in January 1923. The two ships were built by Scotts Shipbuilding and Engineering Company of Greenock on the Firth of Clyde , Scotland. Each had 18 corrugated furnaces with a combined grate area of 385 square feet (36 m) that heated six single-ended boilers with

2294-476: The British Empire started to plan the evacuation of 60,000 British, Australian and New Zealand troops from Greece. Khedive Ismail was one of several troop ships that joined Convoy AG 14, which left Alexandria on 24 April and reached Greek waters two days later. She and a larger troop ship from AG 14, Koninklijke Rotterdamsche Lloyd 's 11,406  GRT Slamat , were sent to evacuate troops from Nauplia in

SS Khedive Ismail - Misplaced Pages Continue

2368-658: The Chilean government introduced protection measures for Chilean companies operating shipping services along the country's 2,300-nautical-mile (4,300 km)-long coast, and in 1923 global shipping rates stabilised. The Wall Street Crash of October 1929 started the Great Depression , which sharply reduced the export market for Chilean mining products and hence the country's ability to buy goods from overseas. CSAV lost trade, and especially on its Valparaíso – New York route, so in June 1931

2442-516: The Italian Giovanni Branca (1629) and John Wilkins in England (1648). The devices described by Taqi al-Din and Wilkins are today known as steam jacks . In 1672, an impulse turbine -driven small toy car was designed by Ferdinand Verbiest . A more modern version of this car was produced some time in the late 18th century by an unknown German mechanic. In 1775 at Soho James Watt designed

2516-637: The Khedivial Mail Line (KML), renamed each ship after a former Khedive of Egypt. Aconcagua became Khedive Ismail , after Isma'il Pasha who reigned 1863–79. KML and operated services linking Alexandria across the Mediterranean Sea with Cyprus , Piraeus , Malta and Marseille . In 1936 the company was reconstituted as the Pharaonic Mail Line, but continued trading as the KML. Although Egypt

2590-504: The bay, where boats would bring troops out to them from the shore. On the evening of 26 April three cruisers, four destroyers, Khedive Ismail and Slamat were in the Bay of Nauplia. The only available tenders were one landing craft, local caïques and the ships' own boats. Two cruisers and two destroyers embarked nearly 2,500 troops, but the slow rate of embarkation meant that Khedive Ismail did not get her turn and did not embark any. At 0300 hrs

2664-1370: The blade speed to the absolute steam velocity at the inlet is termed the blade speed ratio ρ = U V 1 {\displaystyle \rho ={\frac {U}{V_{1}}}} . η b {\displaystyle \eta _{b}} is maximum when d η b d ρ = 0 {\displaystyle {\frac {d\eta _{b}}{d\rho }}=0} or, d d ρ ( 2 cos ⁡ α 1 − ρ 2 ( 1 + k c ) ) = 0 {\displaystyle {\frac {d}{d\rho }}\left(2{\cos \alpha _{1}-\rho ^{2}}(1+kc)\right)=0} . That implies ρ = 1 2 cos ⁡ α 1 {\displaystyle \rho ={\frac {1}{2}}\cos \alpha _{1}} and therefore U V 1 = 1 2 cos ⁡ α 1 {\displaystyle {\frac {U}{V_{1}}}={\frac {1}{2}}\cos \alpha _{1}} . Now ρ o p t = U V 1 = 1 2 cos ⁡ α 1 {\displaystyle \rho _{opt}={\frac {U}{V_{1}}}={\frac {1}{2}}\cos \alpha _{1}} (for

2738-410: The bucket-like shaped rotor blades, as the steam jet changes direction. A pressure drop occurs across only the stationary blades, with a net increase in steam velocity across the stage. As the steam flows through the nozzle its pressure falls from inlet pressure to the exit pressure (atmospheric pressure or, more usually, the condenser vacuum). Due to this high ratio of expansion of steam, the steam leaves

2812-691: The canal, reaching Suez on 30 April. In May 1941 the British Empire occupied Iraq to reverse a pro-German nationalist coup d'état and reinstate King 'Abd al-Ilah , and in June and July it invaded Vichy -controlled Greater Lebanon and Syria whose airfields had refuelled Regia Aeronautica and Luftwaffe flights to northern Iraq . From July 1941 until the beginning of February 1942 Khedive Ismail continually brought British Indian Army reinforcements from India to Basra in Iraq, making seven trips from Bombay and two from Karachi . In January 1942 British and Empire forces had occupied Italian Eritrea , so in

2886-557: The company suspended the service. It sold Aconcagua and Teno to Lithgows of Port Glasgow , and in August 1932 both ships returned to Scotland. Teno was laid up, but Aconcagua was sold to William Hamilton and Company, run by Lord Ernest Hamilton . Lowden Conner and Company of Liverpool were appointed to manage both ships. In 1935 the Khedivial Mail Steamship and Graving Dock Company of Alexandria , Egypt bought both Aconcagua and Teno . The company, which traded as

2960-629: The cosines of the blade angles at the outlet and inlet can be taken and denoted c = cos ⁡ β 2 cos ⁡ β 1 {\displaystyle c={\frac {\cos \beta _{2}}{\cos \beta _{1}}}} . The ratio of steam velocities relative to the rotor speed at the outlet to the inlet of the blade is defined by the friction coefficient k = V r 2 V r 1 {\displaystyle k={\frac {V_{r2}}{V_{r1}}}} . k < 1 {\displaystyle k<1} and depicts

3034-575: The cruiser HMS  Calcutta ordered all ships to sail, but Slamat disobeyed and continued embarking troops. Calcutta and Khedive Ismail sailed at 0400 hrs; Slamat followed at 0415 hrs, by which time she had embarked about 500 troops: about half her capacity. The convoy steamed south down the Argolic Gulf, until at about 0700 hrs waves of Luftwaffe aircraft attacked it: first Bf 109 fighters, then Ju 87 dive bombers and Ju 88 and Do 17 bombers. The attackers concentrated on Slamat as she

SS Khedive Ismail - Misplaced Pages Continue

3108-601: The east coast of the island. She visited the island again in July 1943. On 5 February 1944 Khedive Ismail left Mombasa bound for Colombo carrying 1,348 passengers including 996 members of the East African Artillery's 301st Field Regiment, 271 Royal Navy personnel, 19 WRNS , 53 nursing sisters and their matron, nine members of the First Aid Nursing Yeomanry and a war correspondent , Kenneth Gandar-Dower . She

3182-502: The erosion of the blades in last rows. In most of the cases, maximum number of reheats employed in a cycle is 2 as the cost of super-heating the steam negates the increase in the work output from turbine. Extracting type turbines are common in all applications. In an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sent to boiler feedwater heaters to improve overall cycle efficiency. Extraction flows may be controlled with

3256-1038: The exit of the nozzle is h 2 {\displaystyle h_{2}} . Δ V w = V w 1 − ( − V w 2 ) = V w 1 + V w 2 = V r 1 cos ⁡ β 1 + V r 2 cos ⁡ β 2 = V r 1 cos ⁡ β 1 ( 1 + V r 2 cos ⁡ β 2 V r 1 cos ⁡ β 1 ) {\displaystyle {\begin{aligned}\Delta V_{w}&=V_{w1}-\left(-V_{w2}\right)\\&=V_{w1}+V_{w2}\\&=V_{r1}\cos \beta _{1}+V_{r2}\cos \beta _{2}\\&=V_{r1}\cos \beta _{1}\left(1+{\frac {V_{r2}\cos \beta _{2}}{V_{r1}\cos \beta _{1}}}\right)\end{aligned}}} The ratio of

3330-454: The following companies: Steam turbines are made in a variety of sizes ranging from small <0.75 kW (<1 hp) units (rare) used as mechanical drives for pumps, compressors and other shaft driven equipment, to 1,500 MW (2,000,000 hp) turbines used to generate electricity. There are several classifications for modern steam turbines. Turbine blades are of two basic types, blades and nozzles . Blades move entirely due to

3404-417: The friction due to the blade surface is neglected then η b max = cos 2 ⁡ α 1 {\displaystyle {\eta _{b}}_{\text{max}}=\cos ^{2}\alpha _{1}} . In the reaction turbine , the rotor blades themselves are arranged to form convergent nozzles . This type of turbine makes use of the reaction force produced as

3478-409: The generating capacity of a unit was scaled up by about 10,000 times, and the total output from turbo-generators constructed by his firm C. A. Parsons and Company and by their licensees, for land purposes alone, had exceeded thirty million horse-power. Other variations of turbines have been developed that work effectively with steam. The de Laval turbine (invented by Gustaf de Laval ) accelerated

3552-458: The history of the Commonwealth of Nations . 01°25′N 72°22′E  /  1.417°N 72.367°E  / 1.417; 72.367 Steam turbine#Marine propulsion The steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results in a closer approach to

3626-643: The ideal reversible expansion process. Because the turbine generates rotary motion , it can be coupled to a generator to harness its motion into electricity. Such turbogenerators are the core of thermal power stations which can be fueled by fossil fuels , nuclear fuels , geothermal , or solar energy . About 42% of all electricity generation in the United States in 2022 was by the use of steam turbines. Technical challenges include rotor imbalance , vibration , bearing wear , and uneven expansion (various forms of thermal shock ). In large installations, even

3700-419: The impact of steam on them and their profiles do not converge. This results in a steam velocity drop and essentially no pressure drop as steam moves through the blades. A turbine composed of blades alternating with fixed nozzles is called an impulse turbine , Curtis turbine , Rateau turbine , or Brown-Curtis turbine . Nozzles appear similar to blades, but their profiles converge near the exit. This results in

3774-468: The initial sinking. The seventh torpedo finally destroyed I-27 , sinking her with all hands. The battle had lasted two and a half hours. Of 1,511 people aboard Khedive Ismail , only 208 men and 6 women survived the sinking and subsequent battle. 1,220 men and 77 women were killed. The sinking was the third largest loss of life from Allied shipping in World War II and the largest loss of servicewomen in

SECTION 50

#1732858616837

3848-409: The kinetic energy supplied to the moving blades (m). Or, E {\displaystyle E} = enthalpy drop over the fixed blades, Δ h f {\displaystyle \Delta h_{f}} + enthalpy drop over the moving blades, Δ h m {\displaystyle \Delta h_{m}} . The effect of expansion of steam over the moving blades

3922-642: The loss in the relative velocity due to friction as the steam flows around the blades ( k = 1 {\displaystyle k=1} for smooth blades). η b = 2 U Δ V w V 1 2 = 2 U V 1 ( cos ⁡ α 1 − U V 1 ) ( 1 + k c ) {\displaystyle \eta _{b}={\frac {2U\Delta V_{w}}{{V_{1}}^{2}}}={\frac {2U}{V_{1}}}\left(\cos \alpha _{1}-{\frac {U}{V_{1}}}\right)(1+kc)} The ratio of

3996-463: The middle) before exiting at low pressure, almost certainly to a condenser . The condenser provides a vacuum that maximizes the energy extracted from the steam, and condenses the steam into feedwater to be returned to the boilers. On the left are several additional reaction stages (on two large rotors) that rotate the turbine in reverse for astern operation, with steam admitted by a separate throttle. Since ships are rarely operated in reverse, efficiency

4070-404: The nozzle with a very high velocity. The steam leaving the moving blades has a large portion of the maximum velocity of the steam when leaving the nozzle. The loss of energy due to this higher exit velocity is commonly called the carry over velocity or leaving loss. The law of moment of momentum states that the sum of the moments of external forces acting on a fluid which is temporarily occupying

4144-464: The passengers were below watching an ENSA concert, while others sunbathed on deck. At 1430 hrs the Japanese submarine  I-27 had taken position off Khedive Ismail ' s port side to attack. A lookout sighted I-27 ' s periscope and raised the alarm; Khedive Ismail ' s DEMS gunners opened fire on the submarine. At the same time I-27 ' s commander, Cdr Toshiaki Fukumura, fired

4218-444: The ratio of the work done on the blades to kinetic energy supplied to the fluid, and is given by A stage of an impulse turbine consists of a nozzle set and a moving wheel. The stage efficiency defines a relationship between enthalpy drop in the nozzle and work done in the stage. η s t a g e = W o r k   d o n e   o n   b l

4292-662: The second half of February 1942 Khedive Ismail took 850 troops from Bombay to Massawa . For the next two years she criss-crossed the Indian Ocean in troop movements between Aden, Mombasa, Colombo , Durban , Bombay, Karachi, Tanga , Suez, Diego Suarez , Majunga , Berbera , Port Elizabeth , Cape Town, Djibouti , Tamatave and Dar es Salaam . In September 1942 Khedive Ismail took part in Operation Streamline Jane , taking troops from Allied-occupied Diego Suarez in northern Madagascar to land at Vichy-held Majunga on

4366-400: The stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor. Energy input to the blades in a stage: E = Δ h {\displaystyle E=\Delta h} is equal to the kinetic energy supplied to the fixed blades (f) +

4440-399: The steam accelerates through the nozzles formed by the stator. Steam is directed onto the rotor by the fixed vanes of the stator . It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through

4514-444: The steam enters in the middle of the shaft and exits at both ends, or a combination of any of these. In a double flow rotor, the blades in each half face opposite ways, so that the axial forces negate each other but the tangential forces act together. This design of rotor is also called two-flow , double-axial-flow , or double-exhaust . This arrangement is common in low-pressure casings of a compound turbine. An ideal steam turbine

SECTION 60

#1732858616837

4588-400: The steam to full speed before running it against a turbine blade. De Laval's impulse turbine is simpler and less expensive and does not need to be pressure-proof. It can operate with any pressure of steam, but is considerably less efficient. Auguste Rateau developed a pressure compounded impulse turbine using the de Laval principle as early as 1896, obtained a US patent in 1903, and applied

4662-533: The sturdiest turbine will shake itself apart if operated out of trim. The first device that may be classified as a reaction steam turbine was little more than a toy, the classic Aeolipile , described in the 1st century by Hero of Alexandria in Roman Egypt . In 1551, Taqi al-Din in Ottoman Egypt described a steam turbine with the practical application of rotating a spit . Steam turbines were also described by

4736-410: The survivors. The destruction of a submarine that might sink more ships took precedence over the lives of survivors, so with Paladin out of action Petard resumed the attack with first depth charges, then 4-inch shellfire and finally 21-inch (530 mm) Mk IX torpedoes . The depth charge fuses had to be set to detonate at the most shallow depth, and they killed or wounded many people who had survived

4810-574: The thermal damage and to limit oxidation . These coatings are often stabilized zirconium dioxide -based ceramics. Using a thermal protective coating limits the temperature exposure of the nickel superalloy. This reduces the creep mechanisms experienced in the blade. Oxidation coatings limit efficiency losses caused by a buildup on the outside of the blades, which is especially important in the high-temperature environment. The nickel-based blades are alloyed with aluminum and titanium to improve strength and creep resistance. The microstructure of these alloys

4884-466: The turbine rotor and the casing. This is illustrated in the drawing of the German 1905 AEG marine steam turbine. The steam from the boilers enters from the right at high pressure through a throttle , controlled manually by an operator (in this case a sailor known as the throttleman). It passes through five Curtis wheels and numerous reaction stages (the small blades at the edges of the two large rotors in

4958-722: The turbine to a French torpedo boat in 1904. He taught at the École des mines de Saint-Étienne for a decade until 1897, and later founded a successful company that was incorporated into the Alstom firm after his death. One of the founders of the modern theory of steam and gas turbines was Aurel Stodola , a Slovak physicist and engineer and professor at the Swiss Polytechnical Institute (now ETH ) in Zurich. His work Die Dampfturbinen und ihre Aussichten als Wärmekraftmaschinen (English: The Steam Turbine and its prospective use as

5032-731: The way for a better understanding of the relationship between the various velocities. In the adjacent figure we have: Then by the law of moment of momentum, the torque on the fluid is given by: For an impulse steam turbine: r 2 = r 1 = r {\displaystyle r_{2}=r_{1}=r} . Therefore, the tangential force on the blades is F u = m ˙ ( V w 1 − V w 2 ) {\displaystyle F_{u}={\dot {m}}\left(V_{w1}-V_{w2}\right)} . The work done per unit time or power developed: W = T ω {\displaystyle W=T\omega } . When ω

5106-506: Was a reaction type. His patent was licensed and the turbine scaled up shortly after by an American, George Westinghouse . The Parsons turbine also turned out to be easy to scale up. Parsons had the satisfaction of seeing his invention adopted for all major world power stations, and the size of generators had increased from his first 7.5 kilowatts (10.1 hp) set up to units of 50,000 kilowatts (67,000 hp) capacity. Within Parsons' lifetime,

5180-519: Was forced to the surface. The two destroyers engaged her with their 4-inch (100 mm) QF Mk 5 main guns and Paladin moved to ram her, but as a Type B1 submarine , she was considerably larger than the destroyer so Petard signalled Paladin to abort the manoeuvre. Paladin therefore took avoiding action but too late, and I-27 ' s hydroplane tore a 15-foot (4.6 m) gash in Paladin ' s hull. I-27 submerged again and took refuge beneath

5254-645: Was formally independent , in practice the British Empire exercised control over the country. In 1940 the UK Ministry of War Transport requisitioned seven KML ships and placed Khedive Ismail and her sister ship Mohamed Ali El-Kebir , under the management of the British-India Steam Navigation Company . The two ships were converted into troop ships, which slightly increased their tonnage. Khedive Ismail ' s gross register tonnage (GRT)

5328-564: Was increased from 7,290 to 7,513 tons. Mohamed Ali El-Kebir was sunk in August 1940 on her first troop voyage, en route under Royal Navy escort from Avonmouth to Gibraltar . By then Khedive Ismail was in the Indian Ocean to bring Empire troops to Egypt. From then until April 1941 she carried troops in convoys from Bombay , Cape Town , Mombasa and Port Sudan to Suez and Port Said . In April 1941 Germany and Italy invaded Yugoslavia and Greece . After 10 days of fierce fighting

5402-575: Was part of Convoy KR 8 and it was her fifth convoy on that route. The convoy was escorted by the heavy cruiser HMS  Hawkins and destroyers HMS  Paladin and HMS  Petard . Khedive Ismail was carrying the Convoy Commodore . Early in the afternoon of Saturday 12 February, after a week at sea, KR 8 was in the One and a Half Degree Channel south-west of the Maldives . After lunch many of

5476-598: Was the largest ship. The cruiser HMS  Orion and destroyers Hotspur and Isis , all of which were heavily laden with evacuated troops, escorted Khedive Ismail away as Slamat burned out of control and was abandoned and HMS  Diamond stayed behind to rescue survivors. A few hours later Diamond and another destroyer sent to assist her, HMS  Wryneck , were sunk in another air raid. Khedive Ismail safely reached Souda Bay in Crete , where she joined Convoy GA 14 back to Alexandria. She then continued through

#836163